JP5080855B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle including a lifting mechanism that drives a rotary tiller mounted on the rear of a traveling vehicle body.

  As a conventional technique, for example, as disclosed in Patent Document 1, a working machine (Patent Document 1 of Patent Document 1) is operated by tilting a turning lever (63 in FIG. 1 of Patent Document 1) to the right or left. 2. Description of the Related Art A mobile farm machine having a headland controller (75 in FIG. 1 of Patent Document 1) that automatically raises 14) in FIG. 2 is known.

Japanese Patent No. 3632779 (see FIGS. 1, 2, 5, 8 and paragraph “0020”)

  In the mobile agricultural machine of Patent Document 1, as shown in FIG. 8 of Patent Document 1, the turning direction command switch (64 in FIG. 1 of Patent Document 1) is operated by tilting the turning lever to the right or left. Is switched and a turning direction command is issued, the lift valve (83 in FIG. 1 of Patent Document 1) is lifted to expand and contract the lift cylinder (82 in FIG. 1 of Patent Document 1) linked to the lift valve. The working machine is configured to be lifted, and it is considered that the working machine was lifted at a relatively high speed at a constant speed in order to quickly raise the working machine and turn it quickly.

  When the working machine is lifted at a relatively high constant speed like the mobile farming machine of Patent Document 1, the rotary claws (29 in FIG. 5 of Patent Document 1) of the working machine are vigorously moved from the state of deeply entering the ground. It is thought that a semi-cylindrical tillage trace along the rotation trajectory of the rotary claw was formed on the field. Specifically, for example, as shown in FIGS. 24 (a) and 24 (b), when the rotary (F1 in FIG. 24 (b)) of the work machine rises vigorously from a state of deeply entering the ground, the rotation of the rotary It is considered that the tilling traces having a semicircular arc shape in the side view along the trajectory were formed in the field.

As a result, for example, the tilling marks formed by the rotary claws hinder the operation of the work machine in the field and the subsequent work in the field (for example, scratching work and seedling planting work), and the workability of the farm work in the field is reduced. There was a problem of getting worse.
An object of the present invention is to realize a work vehicle that can prevent generation of tilling marks formed when the rotary tiller is raised from the lowered position, and can improve the workability of farm work on a farm field.

The first feature of the present invention is to configure the work vehicle as follows.
An elevating mechanism for elevating and driving a rotary tiller mounted on the rear of the traveling vehicle body, and an operation instruction means capable of instructing the turning direction of the traveling vehicle body as an operation instruction,
Based on an operation instruction from the operation instruction means, the rotary tiller is raised from the lowered position to the intermediate position at a lower speed than the speed at which the rotary tiller is raised from the preset intermediate position to the raised position. In addition, a tilling device automatic raising means for driving the lifting mechanism is provided ,
An automatic turning control means for automatically turning the traveling vehicle body by steering the front wheel in the turning direction based on an operation instruction from the operation instruction means;
The automatic turning control means performs automatic turning of the traveling vehicle body after the rotary plowing device has risen beyond the set height from the lowered position even if the operation instruction means instructs the turning direction of the traveling vehicle body. Configured to start.

According to the first feature of the present invention, when the rotary tiller is raised from the lowered position to the intermediate position at a low speed by driving the lifting mechanism by the tiller automatic raising means while traveling the traveling vehicle body, for example, FIG. As shown in (b), the rotary tiller (F1 in (b) in FIG. 9) plows the field from the lowered position where it enters the ground, and slowly rises while flying soil etc., and forms at the lowered position. The tilled soil formed when the rotary tiller is raised at a low speed is piled up on the tillage trace of the rotary tiller thus made, and the tillage trace formed at the lowered position can be reduced. As a result, it is possible to prevent the occurrence of tilling marks formed when the rotary tiller is raised from the lowered position.

  According to the first feature of the present invention, the rotary tiller rises at a higher speed than the speed at which the rotary tiller rises to the intermediate position above the intermediate position. Thus, the rotary tiller can be quickly raised to the lift position, and the rotary tiller can be efficiently lifted to the lift position. As a result, for example, it is possible to efficiently lift the rotary tiller to the raised position and turn the work vehicle.

According to the first feature of the present invention, for example, a tilled trace formed by raising a rotary tiller device is unlikely to obstruct the work vehicle when traveling on the field, and the work vehicle can be driven without difficulty. The workability of farm work on the farm can be improved. In addition, for example, the tilled trace formed by raising the rotary tiller device is unlikely to hinder subsequent work in the field (for example, pricking work or seedling planting work), thereby improving the workability of the farm work in the field. be able to.

  According to the first feature of the present invention, for example, the rotary tiller device is less likely to interfere with turning the work vehicle, and the work vehicle can be turned without difficulty, thereby improving the workability of the turning work of the work vehicle. be able to.

In addition, according to the first feature of the present invention, when the operation instruction is issued by the operation instruction means, the lifting mechanism can be automatically driven by the tiller automatic raising means, and the front wheels are automatically turned in the turning direction by the automatic turning control means. The traveling vehicle body can be automatically turned by steering. As a result, it is possible to use both the operating means for driving the lifting mechanism and the operating means for automatically turning the traveling vehicle body, for example, as compared with the case of driving the lifting mechanism and the automatic turning of the traveling vehicle body by separate operating means. In addition, it is possible to simply and quickly drive the lifting mechanism and automatically turn the traveling vehicle body with one operation instruction means.

According to the first feature of the present invention, the workability of driving the lifting mechanism and the automatic turning of the traveling vehicle body can be improved, and the workability of farming work (cultivation work) on the field can be further improved.

Further, according to the first feature of the present invention, the steering operation of the front wheels is regulated by the automatic turning control means until the rotary tiller rises to the set height from the lowered position where the rotary tiller enters the ground, and the rotary tiller is It is possible to prevent the traveling vehicle body from turning in a state where it has entered deep into the ground. As a result, for example, when the rotary tillage device is configured to start the steering operation of the front wheels almost simultaneously with raising the rotary tillage device, the rotary tillage device that has entered the ground can be It can move, and it can prevent that a tilling trace is formed in a farm field by lateral movement of this rotary tiller. Further, for example, an excessive force can be prevented from acting on the rotary tiller as in the case where the steering operation of the front wheels is started almost simultaneously with raising the rotary tiller.

According to the first feature of the present invention, it is possible to prevent the generation of till marks formed when the rotary tiller is turned and to prevent the rotary tiller from being damaged.

The second feature of the present invention resides in the following configuration.
A rising speed adjusting means capable of changing and adjusting a speed at which the rotary tiller is raised at a low speed is provided at the intermediate position.

According to the second feature of the present invention, by changing and adjusting the ascent speed adjusting means, the speed at which the rotary tiller is raised at low speed by the tiller automatic raising means can be changed manually or automatically. Depending on the conditions (for example, the hardness of the field, the depth of plowing the field, etc.) and the conditions (for example, the hardness of the field, the depth of plowing the field, etc.) The raising speed can be changed manually or automatically. As a result, it is possible to prevent the occurrence of tillage marks formed when the rotary tiller is raised from the lowered position in accordance with the conditions of the tillage work and the field.

  Specifically, for example, when the soil in the field is relatively hard and plowing marks by the rotary tiller are likely to occur, compared to when the soil in the field that is difficult to plow by the rotary tiller is relatively soft , Change the speed of raising the rotary tiller at low speed slowly, raise the rotary tiller at low speed while plowing for a longer time, a lot of soil etc. on the tillage mark formed at the lowered position Can be cultivated, and tillage marks can be reduced.

According to the second feature of the present invention, the field can be efficiently cultivated according to the conditions of the tillage work, the field, etc., and the workability of the tillage work can be improved.

The third feature of the present invention resides in the following configuration.
An intermediate position adjusting means capable of changing and adjusting the intermediate position is provided.

According to the third feature of the present invention, by changing and adjusting the intermediate position by the intermediate position adjusting means, the intermediate position for raising the rotary tiller at low speed by the tiller automatic raising means can be changed manually or automatically, Intermediate position depending on conditions of tillage work (for example, tilling speed, turning speed, type of rotary tiller mounted on the work vehicle, etc.) and conditions of the field (for example, the hardness of the field, the depth of plowing the field, etc.) Can be changed manually or automatically. As a result, it is possible to prevent the occurrence of tillage marks formed when the rotary tiller is raised from the lowered position in accordance with the conditions of the tillage work and the field.

  Specifically, for example, when the soil in the field is relatively hard and plowing marks by the rotary tiller are likely to occur, compared to when the soil in the field that is difficult to plow by the rotary tiller is relatively soft By changing the middle position to a higher position, raising the rotary tillage device while plowing for a longer distance, it is possible to pile a lot of soil etc. on the tillage mark formed at the lowered position. Traces can be reduced.

According to the third feature of the present invention, the field can be efficiently cultivated according to the conditions of the tillage work, the field, etc., and the workability of the tillage work can 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 a tilling device F (corresponding to a rotary tilling device) 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. 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, an orientation sensor 39, and a yaw rate sensor 40. , Lift position detection sensor 41, turning angle adjuster 42, ascent speed adjuster 43 (corresponding to ascending speed adjuster), intermediate position adjuster 44 (corresponding to intermediate position adjuster), front wheel break angle sensor 66, vehicle speed sensor 67 Etc. are installed.

  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 the operation instruction means) is provided on the side of the driver's seat 5, and the turning lever 37 can instruct turning and turning directions 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.

  At the side of the driver's seat 5, a turning angle adjuster 42 for setting a turning angle for automatic turning control, which will be described later, an ascending speed adjusting tool 43 for setting an ascending speed of automatic turning control, and an intermediate position of the automatic turning control The intermediate position adjusting tool 44 for setting the turning angle is adjusted, and the turning angle adjusting tool 42, the ascending speed adjusting tool 43 or the intermediate position adjusting tool 44 is dialed to turn the turning angle and the rising speed in automatic turning control to be described later. Alternatively, the intermediate position 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).

  Thus, based on the operation instruction from the turning lever 37, the speed of the tiller F is raised from the preset intermediate position to the raised position at a lower speed and the tiller F is raised from the lowered position to the intermediate position at a lower speed. The tilling device automatic raising means is configured so as to make it happen.

  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).

  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. 24 and FIG. 25, the turning state of the tractor when the above-described automatic linear advance control and automatic turn 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.

  24 and 25 are schematic views for explaining the turning situation of the conventional tractor, and correspond to FIGS. 9 and 10, respectively. FIG. 25 (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. 24 (a) and 24 (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. 24 (a), the tiller that has entered the ground by turning the tractor in a state where the rotary F1 of the tillage device F has not come out of the 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 FIG. 9 (B) and FIG. 24 (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. 25 (a) and 25 (b), the left and right front wheels 3, 3 are automatically steered 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], an example in which the tractor is automatically turned by operating the turning lever 37 has been shown. The tractor may be configured to automatically turn. Other configurations other than those described later are the same as those described in [Best Mode for Carrying Out the Invention].

[Block diagram of control device]
As shown in FIG. 13, a GPS receiver 70, a navigation system 71, a monitor 72, and an operation position detection sensor 74 are connected to the control device 31, and the tractor is not equipped with the straight advance lever 35 and the turning lever 37. By operating the monitor 72 instead of the straight advance lever 35 and the turning lever 37, the tilling operation can be performed in a fully automatic operation.

  The GPS receiver 70 is configured as an SBAS receiver corresponding to an SBAS (stationary satellite type satellite navigation augmentation system), and receives position information from a GPS satellite (not shown) and a reference station (not shown). It is configured to receive correction information for aviation.

  A GPS antenna 19 mounted on the front portion of the steering handle 6 is connected to the GPS receiver 70 (see FIG. 12). Position information from GPS satellites received by the GPS receiver 70, and the GPS receiver 70 are also included. The correction information from the reference station received by is input to the control device 31, and the current position of the tractor is detected with an error of, for example, several centimeters.

  The navigation system 71 provides map information, and is configured such that a menu display screen M, which will be described later, is displayed on the monitor 72 mounted on the side of the steering handle 6 together with the map information of the navigation system 71. Has been.

  The monitor 72 is configured as a touch panel, and includes a body condition setting screen M1, a turning condition setting screen M2, a field area setting screen M3, a tilling area setting screen M4, and a fully automatic operation screen M5 from a menu display screen M described later. It is configured so that it can be selected and displayed. An operation button (not shown) may be provided on the side of the monitor 72 so that a display screen, a setting button, and the like displayed on the monitor 72 described later can be selected by the operation button.

  The forward / reverse switching lever 73 is provided on the side of the driver's seat 5 and can switch forward and backward of the traveling vehicle body 1. The operation position of the forward / backward switching lever 73 (forward position, neutral position and The reverse position) can be detected by the operation position detection sensor 74.

[How to operate the monitor]
A method for operating the monitor 72 will be described with reference to FIGS. As shown in FIG. 14, the menu display screen M is displayed on the monitor 72 when the control device 31 is activated. On the menu display screen M, icons of the machine condition setting M1, the turning condition setting M2, the field area setting M3, the tilling area setting M4, and the fully automatic operation M5 are displayed. When this icon screen is touched with a finger, each icon is displayed. The screen is selected and displayed on the monitor 72.

  As shown in FIG. 15 (a), when the machine condition setting screen M1 is selected from the menu display screen M of the monitor 72, a setting screen for the machine length, the machine width, and the type of the tillage device F is displayed. By touching the adjustment button R1 of the machine width with a finger, the respective values are changed and the machine length and the machine width can be changed. When the model button R2 (F-A to F-D) of the tillage device F is selected, The machine length and machine width stored in advance according to the type of the tillage device F are automatically displayed on the body condition setting screen M1, and the body condition can be automatically set according to the type of the tillage device F. .

  When the setting of the machine condition is completed and the setting end button R3 is pressed, the machine condition is changed and the menu display screen M is displayed again. The machine condition setting screen M1 is provided with a clear button R4 and a reset button R5. When the clear button R4 is pressed, the immediately preceding machine condition is displayed, and is initialized by pressing the reset button R5. Aircraft conditions are displayed.

  As shown in FIG. 15B, when the turning condition setting screen M2 is selected from the menu display screen M of the monitor 72, the setting screen for the ascending speed and the intermediate position is displayed, and each adjustment button S1 is touched with a finger. Each value can be changed to change the rising speed or the intermediate position. Thus, the ascending speed adjusting means and the intermediate position adjusting means are configured so that the ascending speed or the intermediate position can be changed by touching the monitor 72 with a finger.

  When the setting of the turning condition is completed and the setting end button S2 is pressed, the turning condition is changed and the menu display screen M1 is displayed again. The turning condition setting screen M2 includes a clear button S3 and a reset button S4. When the clear button S3 is pressed, the immediately preceding turning condition is displayed, and the turning condition setting screen M2 is initialized by pressing the reset button S4. The turning condition is displayed.

  As shown in FIG. 16, when the field area setting screen M3 is selected from the menu display screen M of the monitor 72, various buttons are displayed together with the map information of the navigation system 71. By pressing the field area setting start button T1, the field area The setting or change can be started.

  When the position of the GPS antenna 19 in a plan view (the position of the front central portion of the steering handle 6 of the tractor) is input to the control device 31 by the GPS receiver 70 as the current position, and the field area setting screen M3 is selected, Based on the current position received by the GPS receiver 40 and the vehicle body conditions (such as the width of the working device and the total length of the traveling vehicle body 1) input to the control device 31 in advance, the right side of the tillage device F installed at the rear of the tractor The rear end position is calculated by the control device 31.

  Press the field area setting start button T1, move the tractor to the four corners (P1 to P4) of the field area to be set or changed (position the right rear end of the tillage device F at the four corners), and set the area at each position. By pressing the setting button T2, the field area by the tractor (area surrounded by P1 to P4) is automatically set on the map information provided by the navigation system 71, and this field area is the field of the monitor 72. The area setting screen M3 is configured to be displayed together with the map information of the navigation system 71. In addition, you may comprise so that an agricultural field area | region may be set by inputting into the control apparatus 31 the positional information on P1-P4 of an agricultural field area | region.

  The field area setting work is stored in the control device 31 by setting it once for the first time in the field where the field work is performed for the first time, and in the second and subsequent field work, the tractor is moved close to the field area. By displaying the farm field setting screen M3, the tilling area setting screen M4 or the fully automatic operation screen M5 on the monitor 72, the farm field area is automatically displayed on each screen. When changing the field area, the field area can be changed by resetting according to the above-described procedure.

  When the setting or change of the field area is completed and the field area setting end button T4 is pressed, the field area is set or changed, and the menu display screen M1 is displayed again. The field area setting screen M1 is provided with a clear button T3, and the previous field area is displayed by pressing the clear button T3.

  As shown in FIG. 17, when the tillage area setting screen M4 is selected from the menu display screen M of the monitor 72, various buttons are displayed together with the map information and the field area of the navigation system 71, and by pressing the tillage area setting start button U1. The setting or changing of the tillage area can be started.

  When the position of the GPS antenna 19 in plan view (the position of the center of the front part of the steering handle 6 of the tractor) is input to the control device 31 by the GPS receiver 70 as the current position, and the tillage area setting screen M4 is selected, Based on the current position received by the GPS receiver 40 and the vehicle body condition (positional relationship from the GPS antenna 19 to the rear of the driver seat 5) input to the control device 31 in advance, the vehicle is equipped at the rear of the traveling vehicle body 1. The position of the driver seated on the driver's seat 5 is configured to be processed by the control device 31.

  Push the cultivation area setting start button U1 and move the tractor to the four corners (Q1 to Q4 in FIG. 17) of the cultivation area where the cultivation is performed in the field area to be set (the driver's seat while checking the position with the eyes) When the rear portion of the 5 is positioned at the four corners and the tilling region setting button U2 is pressed at this moved position, the outer periphery of the field region (P1 to P4 in FIG. 16) is displayed on the map information provided by the navigation system 71. ) Is automatically set (a dotted line connecting Q1 to Q4 in FIG. 17), and this tillage area is displayed on the tillage area setting screen M4 of the monitor 72 with the map information of the navigation system 71 and Displayed with the field area.

  It is not necessary to move the tractor to the position where the tilling area is set by selecting one of the tilling lines (G1 to G4) displayed on the tilling area setting screen M4 with a finger and pressing the adjustment button U3. In addition, the tilling area can be set on the screen, and the fine adjustment and change of the tilling area already set on the screen can be performed without moving the tractor to the position where the tilling area is set.

  When the setting or change of the cultivation area is completed and the cultivation area setting end button U5 is pressed, the cultivation area is set or changed, and the menu display screen M is displayed again. The tillage area setting screen M4 is provided with a clear button U4. When the clear button U4 is pressed, the immediately previous tillage area is displayed.

  As shown in FIG. 18, when the fully automatic operation screen M5 is selected from the menu display screen M of the monitor 72, it is detected by the map information, the field area, the tilling area, the current position of the tractor and the operation position detection sensor 74 of the navigation system 71. Various buttons are displayed together with the operation position of the forward / reverse switching lever 73 (the traveling direction of the traveling vehicle body 1). On the fully automatic operation screen M5, together with the information described above, a tilling path H (setting position) for tilling work by the tractor is displayed. By moving the tractor to the tilling work starting position A0 and pressing the start button W1 A fully automatic operation to be described later is performed along the preset tillage path H.

  The straight running portion of the tillage path H is automatically calculated by the control device 31 so that the entire area of the tillage area can be plowed without gaps based on the tiller area and the body condition set on the body condition setting screen M1. To be set. Further, the turning portion of the tillage path H includes the tilling area, the field area, the body condition set on the body condition setting screen M1, and the turning conditions set on the turning condition setting screen M2, based on the turning conditions set on the turning condition setting screen M2. The turning radius at which the tractor can turn in the area between the two and the turning angle necessary for adjacent plowing are automatically calculated and set by the control device 31.

  The fully automatic operation screen M5 is provided with a selection button W2, and when this selection button W2 is pressed, a plurality of tilling patterns (patterns of tillage path H on which tilling work is performed by a tractor) are displayed on the screen of the monitor 72. A plurality of tilling patterns can be selected (the tilling path H displayed in FIG. 18 is an example). The fully automatic operation screen M5 includes an interrupt button W3 and an end button W4. When the interrupt button W3 is pressed, the fully automatic operation can be temporarily interrupted, and by pressing the end button W4, The fully automatic operation ends and the menu display screen M is displayed.

[Automatic linear control and automatic turning control]
Based on FIGS. 19-22, the automatic straight-ahead control and automatic turning control which are implemented with this tractor are demonstrated. FIG. 19 shows a main routine of the control device 31, and FIG. 20 shows a subroutine in the case where automatic linear control is performed. 21 to 22 show subroutines when automatic turning control is performed.

  As shown in FIG. 19, data detected by the detection devices shown in FIG. 13 and input to the control device 31 is monitored (step # 51). When it is determined that the tractor has entered the tillage area (passed the tillage lines G1 to G4) based on the current position received by the GPS receiver 70 and the preset tillage area (YES in step # 52). Then, automatic straight-ahead control to be described later is performed (step # 53).

  On the other hand, when it is determined that the tractor has left the tillage area (passed through the tillage lines G1 to G4) based on the current position received by the GPS receiver 70 and the preset tillage area (step # 54. (YES), automatic turning control described later is performed (step # 55). In addition, after a tractor enters a tilling area | region, when a tractor comes out of a tilling area | region, the automatic rectilinear advance control and automatic turning control which are mentioned later are implemented in duplicate.

  As shown in FIG. 20, when the tractor enters the tilling region and the automatic linear advance control is performed, the lift cylinder 9 is shortened so that the tilling device F is lowered to the lowered position by being output from the control device 31 to the electromagnetic valve 46. (Step # 61), the rear wheel differential 63 is output from the control device 31 to the differential lock actuator 56, and the left and right rear wheels 4, 4 are rotated at substantially the same rotational speed to improve the straightness of the tractor. (Step # 62). 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 driven.

  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 # 63).

  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 # 64), 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 move the tractor straight) (Step # 64, NO), based on the current position received by the GPS receiver 70 and the preset tillage path H, it is determined whether or not the current position of the traveling vehicle body 1 has deviated from the tillage path H (set position). (Step # 65).

  When it is determined that the current position received by the GPS receiver 70 has deviated from the tillage path H (step # 65, YES), the front wheel 3 is steered in a direction opposite to the direction deviated from the tillage path H. As described above, the controller 31 outputs an output to the motor drive circuit 45 to drive the steering motor 30 to automatically steer the tractor so as to move along the preset tillage path H (step # 66). ).

  When it is determined that the current position of the traveling vehicle body 1 has been corrected to the tillage path H based on the current position received by the GPS receiver 70 and the preset tillage path H (step # 67 YES), control is performed. The steering motor 30 is stopped by cutting off the output from the device 31 to the motor drive circuit 45 (step # 68).

  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 # 64 to # 68) (# 69, NO), the current position of the tractor is corrected and the tractor is driven along the tillage path H.

  When it is determined that the driver steers the steering handle 6 to the right or left, the driver's intention to operate the steering handle 6 is given priority (step # 64 YES), and the steering motor 30 is The automatic rectilinear control is terminated without forward and reverse rotation, and the front wheel 3 is steered according to the operation of the steering handle 6 by the driver.

  As described above, by rotating the steering motor 30 constituting the steering differential mechanism 20 forward and backward, the steering device 12 is automatically operated so that the traveling vehicle body 1 moves to a preset tillage path H (set position). It is configured to automatically steer along.

  In addition, when the automatic linear control is canceled by automatic turning control described later while the automatic linear control is being performed, the automatic linear control is automatically terminated (step # 69 YES). .

  As shown in FIGS. 21 and 22, when the tractor leaves the tilling area, automatic turning control is performed, and the lift cylinder is output from the control device 31 to the solenoid valve 46 so that the tilling device F rises to an intermediate position at a low speed. 9 is expanded (step # 71).

  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 # 72), and if it is determined that the tilling device F has been raised to the intermediate position ( (Step # 72, YES), the above-described automatic straight-ahead control is canceled (step # 73, step # 69, YES).

  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 solenoid valve 46 to the solenoid valve 46 so that the tilling device F rises to the raising position at a high speed (step # 74). ). 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.

  In this way, an operation instruction is issued from the control device 31 based on the cultivation area, the cultivation path H, and the current position received by the GPS receiver 70, and the cultivation device F rises to an intermediate position at a low speed. The operation instruction means is configured so that the tractor automatically turns after being raised to the intermediate position.

  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 traveling transmission is electrically shifted to a preset number of gears for turning, and is automatically changed to the vehicle speed for turning (step # 75).

  Next, the rear wheel differential 63 output from the control device 31 to the differential lock actuator 56 and operated by the automatic linear advance control is unlocked (step # 76).

  Next, it is output from the control device 31 to the motor drive circuit 45 so that the tractor turns along the tillage path H in a preset direction (left direction L or right direction R). The steering motor 30 is driven to turn (step # 77).

  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 # 78), and the rotational speed of the front wheel 3 is shifted to the high speed side (step # 79). Then, the control device 31 outputs the operation valve 54 to operate the brake cylinder 53 to operate the side brake 62 on the turning center side to the braking side to turn the tractor in a small turn.

  The control device 31 is configured so that the series of control of Steps # 73 to # 79 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 is quickly turned. It is configured to be changeable.

  Based on the detection result of the front wheel break angle sensor 66, it is determined whether the front wheels 3 and 3 have been operated to a preset front wheel steering angle (step # 80), and the steering motor 30 is driven to turn to turn the tractor. When the front wheels 3 and 3 are operated at the front wheel steering angle corresponding to the preset turning radius to be made (step # 80, YES), the output from the control device 31 to the motor drive circuit 45 is cut off. Then, the steering motor 30 is stopped, and the state in which the front wheels 3 and 3 are operated at a predetermined front wheel steering angle is maintained (step # 81).

  Next, the tractor is turned while the front wheels 3 and 3 are operated at a predetermined front wheel steering angle, and the tractor is preset based on the current position received by the GPS receiver 70 and the preset tillage path H. It is determined whether or not the vehicle has made the turning angle (step # 82). If it is determined that the tractor has turned to the turning angle (step # 82, YES), the front wheel 3 is steered in the direction opposite to the direction in which the tractor is turned by outputting to the motor drive circuit 45 from the control device 31. As described above, the steering motor 30 is gradually reversely driven (step # 83), and the front wheel 3 is determined based on the current position received by the GPS receiver 70, the detection result of the front wheel break angle sensor 66, and the tilling path H. Adjacent plowing is performed automatically to the adjacent plowing so that is in a straight direction.

  When the tractor is adjacently plowed to the adjacent plowing (step # 84), a buzzer is sounded or the lamp is turned on by outputting the control device 31 to the display device 57, and the driver completes the turning of the tractor. This is visually or audibly notified (step # 85), and the automatic turning control is terminated.

  The turn end position of the tractor is set so that it immediately enters the tilling area (step # 52) upon completion of the automatic turning control, and when the automatic turning control is finished, the above-described automatic straight running control is immediately implemented, and thereafter The control (step # 53) and the automatic turning control (step # 54) are alternately repeated, and when the tilling work in the entire tillage region is finished, the fully automatic operation is finished.

[Status of tractor tillage work]
Based on FIG. 23, the tilling situation of the tractor when the fully automatic operation described above is performed will be described. FIG. 23 is a schematic plan view for explaining a situation where the tractor goes straight and turns. As shown in FIG. 23, when the tractor is moved to the point A0, the monitor 72 is switched to the fully automatic operation screen M5, and when the start button W1 is pressed and the tractor enters the tillage area, the automatic straight-ahead control is performed and the tillage path H The tractor automatically goes straight along.

  When the tractor travels straight to the A1 point, the tillage device F automatically starts to rise at the A1 point, and the automatic straight travel control is continued for a distance L1 from the A1 point to travel to the B1 point. And a tractor turns automatically by automatic turning control.

  When the tractor turns to the point C1 and ends the turn, the adjacent plowing is automatically performed adjacent to the point D1, and the automatic turning control ends at the point D1. Then, automatic linear movement control is performed again at the point D1, and thereafter, automatic linear movement and automatic turning are alternately repeated, and when the tilling work in the entire cultivation area is completed, the fully automatic operation is completed.

  As described above, by simply operating the monitor 72, the tractor is configured to perform full-automatic automatic straight advance and automatic turn, so that the driver only sits on the driver's seat 5 and holds the steering handle 6. The plowing area can be automatically cultivated, and in addition to the steering operation for moving the traveling vehicle body 1 straight and the steering operation for turning the traveling vehicle body 1, no adjacent plowing work is required, and the traveling vehicle body 1 is moved straight and turned In addition, it is not necessary to pay attention to the operation of the steering handle 6 for adjacent farming, and the traveling vehicle body 1 can be easily moved straight, turned, and adjacently farmed. It is possible to efficiently perform tillage work while confirming the above.

[Second Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] and [First Alternative Embodiment of the Invention], the lower end of the rotary F1 is substantially the same as the field scene in the intermediate position where the tilling device F is raised at a low speed. Although the set example is shown, the intermediate position may be set higher or lower, and the intermediate position is a position where the lower end of the rotary F1 enters the ground, or a position where the lower end of the rotary F1 rises up from the field scene. May be set.

  In the above-mentioned [Best Mode for Carrying Out the Invention] and [First Different Embodiment of the Invention], the traveling vehicle body 1 starts to turn automatically at substantially the same time as the tillage device F rises to the intermediate position. However, the timing at which the tilling device F rises to the intermediate position and the timing at which the traveling vehicle body 1 starts the automatic turning may be different timings. Automatic turning control may be performed so that the traveling vehicle body 1 starts automatic turning earlier than the intermediate position rises, and the traveling vehicle body 1 starts automatic turning after the tillage device F rises to the intermediate position. Automatic turning control may be performed.

  In the above-mentioned [Best Mode for Carrying Out the Invention] and [First Alternative Embodiment of the Invention], an example in which the operation instruction means is configured to issue an operation instruction by the turning lever 37 or the control device 31. Although shown, a different configuration may be adopted as an operation instruction means for issuing an operation instruction. For example, an operation instruction is issued by an operation tool such as a switch (not shown) or a touch panel type screen operation. Means may be configured.

  In the above-mentioned [Best Mode for Carrying Out the Invention], the ascent speed and the intermediate position of the tillage device F can be manually changed and adjusted by the dial operation of the ascent speed adjuster 43 or the intermediate position adjuster 44. Although an example in which the ascent speed adjusting means and the intermediate position adjusting means are configured is shown, the control apparatus 31 may be configured so that the ascent speed or the intermediate position of the tilling device F can be automatically changed and adjusted. The lift speed 8 or the intermediate position can be automatically changed and adjusted based on the position of the lift arm 8 (cultivation device F) detected by 41, the descent position of the tillage device F set by the tillage depth adjuster, etc. The ascending speed adjusting means and the intermediate position adjusting means may be configured.

  In this way, by configuring the ascending speed adjusting means or the intermediate position adjusting means so that the ascending speed or the intermediate position can be automatically changed and adjusted, the ascending speed or the intermediate position according to the height of the tillage device F or the tilling depth. Can be changed, and the occurrence of tillage marks can be more effectively prevented.

  In the above-mentioned [Best Mode for Carrying Out the Invention], the ascent speed and the intermediate position of the tillage device F can be changed and adjusted by the dial operation of the ascent speed adjuster 43 or the intermediate position adjuster 44. The example which comprised the adjustment means and the intermediate position adjustment means is shown, and in the above-mentioned [the 1st another form of embodiment of the invention], the raising speed and intermediate position of the tillage device F are changed by the turning condition setting screen M2 of the monitor 72 Although an example in which the ascending speed adjusting means and the intermediate position adjusting means are configured so as to be adjustable is shown, different configurations may be adopted as the ascending speed adjusting means and the intermediate position adjusting means, for example, switching to a plurality of operation positions is possible. Ascent speed adjusting means and an intermediate position can be changed and adjusted by a constant operation switch (not shown) by a constant speed or a constant height. It may constitute an intermediate position adjusting means.

[Third Another Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention], [First Another Mode of Carrying Out the Invention] and [Second Another Mode of Carrying Out the Invention], when shifting to the automatic turning control, the tillage device F is set in advance. Automatic raising of the tilling device so that the tilling device F is raised from the lowered position to the intermediate position at a lower speed (first raising speed V1) than the speed at which it is raised from the set intermediate position to the raising position (second raising speed V2). Although the example which comprised the means was shown, the 1st raising mode which raises the tillage apparatus F from a descending position to a raising position at high speed (for example, 2nd raising speed V2), and low speed (from the descending position to an intermediate position) For example, an artificial operating tool (not shown) provided in the vicinity of the driver's seat 5 with a second ascending mode in which it is raised at a first ascent speed V1) and raised at a high speed (for example, a second ascent speed V2) from the intermediate position to the ascending position. To switch It makes may be selectably configured by the driver in accordance with the conditions of the tilling.

  Thus, by raising the tillage device F to an intermediate position at a low speed as necessary, for example, when it is difficult to generate tillage marks in the field, the first raising mode is selected and the tiller device F is raised. Priority can be given to the tractor and the tractor can be turned quickly. For example, when a farming trace is likely to occur in the field, the second rising mode can be selected to effectively prevent the farming trace from occurring.

  In the above-mentioned [Best Mode for Carrying Out the Invention], [First Alternative Embodiment of the Invention] and [Second Alternative Embodiment of the Invention], the tillage device F is lifted from a preset intermediate position. An example is shown in which the tilling device automatic raising means is configured to raise the tillage device F from the lowered position to the intermediate position at a lower speed (first raising speed V1) than the speed of raising to the position (second raising speed V2). However, a high speed mode in which the tilling device F is raised from the lowered position to the raised position at a high speed (for example, the second ascent speed V2) and a speed lower than the speed at which the tiller F is raised in the high speed mode (for example, the first ascent speed V1). ) By operating an artificial operating tool (not shown) provided in the vicinity of the driver's seat 5 in the low speed mode in which the tilling device F is lifted from the lowered position to the raised position. Cut by For example to be able to be configured.

  Thus, by raising the tillage device F at a low speed as necessary, for example, when it is difficult to generate tillage marks on the field, the high speed mode is selected to prioritize the raising of the tillage device F, The tractor can be turned quickly, and for example, when tillage marks are likely to occur in the field, the low speed mode can be selected to effectively prevent the occurrence of tillage marks, and there is no need to provide an intermediate position. Therefore, generation of tillage marks can be prevented with a simple configuration.

[Fourth Embodiment of the Invention]
In the above [Best Mode for Carrying Out the Invention], [First Alternative Embodiment of the Invention], [Second Alternative Embodiment of the Invention] and [Third Alternative Embodiment of the Invention] As an example of a car, an example in which automatic straight control, automatic turning control and fully automatic operation are applied to a tractor equipped with a tillage device F has been shown, but it can be similarly applied to different work vehicles with different work devices, By applying it to a rice transplanter equipped with a planting device, it is possible to improve the workability of seedling planting work by running straight ahead with high accuracy, and it is possible to improve the workability of turning work at the shore 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 Whole left side view of the tractor in the first alternative embodiment of the invention The block diagram of the control apparatus in 1st another form of implementation of invention Menu display screen of the monitor according to the first embodiment of the invention Airframe condition setting screen and turning condition setting screen according to the first embodiment of the invention Agricultural field area setting screen according to the first embodiment of the invention Tillage area setting screen in the first alternative embodiment of the invention Fully automatic operation screen in the first alternative embodiment of the invention The flowchart of the main routine of the control apparatus in 1st another form of implementation of invention Flowchart of automatic straight-ahead control in the first alternative embodiment of the invention Flowchart of automatic turning control in the first alternative embodiment of the invention Flowchart of automatic turning control in the first alternative embodiment of the invention The schematic plan view for demonstrating the condition where the tractor in the 1st another form of implementation of the invention 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

1 Traveling body 3 Front wheel 8 Lift arm (elevating mechanism)
9 Lift cylinder (elevating mechanism)
37 Turning lever (operation instruction means)
43 Climbing speed adjuster (Climbing speed adjusting means)
44 Intermediate position adjustment tool (Intermediate position adjustment means)
F tillage device (rotary tillage device)

Claims (3)

An elevating mechanism for elevating and driving a rotary tiller mounted on the rear of the traveling vehicle body, and an operation instruction means capable of instructing the turning direction of the traveling vehicle body as an operation instruction,
Based on an operation instruction from the operation instruction means, the rotary tiller is raised from the lowered position to the intermediate position at a lower speed than the speed at which the rotary tiller is raised from the preset intermediate position to the raised position. a, Ri Oh comprises a plow automatic raising means for driving the elevating mechanism,
An automatic turning control means for automatically turning the traveling vehicle body by steering the front wheel in the turning direction based on an operation instruction from the operation instruction means;
The automatic turning control means performs automatic turning of the traveling vehicle body after the rotary plowing device has risen beyond the set height from the lowered position even if the operation instruction means instructs the turning direction of the traveling vehicle body. A work vehicle configured to start . The work vehicle according to claim 1, further comprising an ascent speed adjusting means capable of changing and adjusting a speed at which the rotary tiller is raised at a low speed at the intermediate position . The work vehicle according to claim 1, further comprising intermediate position adjusting means capable of changing and adjusting the intermediate position .

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