Work vehicle

Abstract

To provide a work vehicle which improves workability when starting automatic travel.SOLUTION: A work vehicle comprises: a traveling vehicle body; a working machine which is mounted on the traveling vehicle body and can move up and down to a predetermined work position and a predetermined non-work position; a positioning device which detects a position of the traveling vehicle body; and a control device which causes the traveling vehicle body to perform automatic travel along a straight line based on the detected position of the traveling vehicle body. When input operation is made for starting the automatic travel, the control device puts the automatic travel into an operating state regardless of a lifting height of the working machine. When the height of the working machine is detected to be equal to or higher than a predetermined height which is higher than the predetermined work position after putting the automatic travel into the operating state, the control device put the automatic travel into a non-operating state.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a work vehicle.

Background Art

[0002] Conventionally, in a field, a work vehicle that performs planting while automatically traveling is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above technology, when starting automatic traveling, the height of the seedling planting part is not regulated, and there is room for improvement in workability at the start of automatic traveling.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a work vehicle that improves workability when starting automatic traveling.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a work vehicle (1) according to one aspect of the embodiment includes a traveling vehicle body (2), a work implement (50) attached to the traveling vehicle body (2) and capable of being raised and lowered to a predetermined work position and a predetermined non-work position, a position measuring device (150) for detecting the position of the traveling vehicle body (2), and a control device (150) for automatically driving the traveling vehicle body (2) along a straight line based on the detected position of the traveling vehicle body (2). When an input operation for starting the automatic driving is performed, the control device (150) activates the automatic driving regardless of the lifting height of the work implement (50), and after activating the automatic driving, if it is detected that the height of the work implement (50) is equal to or higher than a predetermined height that is higher than the predetermined work position, the automatic driving is deactivated.

Effect of the Invention

[0007] According to one aspect of the embodiment, the work vehicle improves workability when starting automatic driving.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0009] Hereinafter, a work vehicle according to an embodiment of the present invention will be described in detail with reference to the drawings using a ride-on type seedling transplanter 1 as an example. Note that the constituent elements in the following embodiments include those that can be replaced and easily implemented by those skilled in the art, or those that are substantially the same, that is, those within the so-called equivalent range. Furthermore, the present invention is not limited to the above embodiments, and can be implemented with various modifications without departing from the gist of the present invention. In the following description, the entire seedling transplanter 1 may be referred to as the machine body.

[0010] Figure 1 is an explanatory view showing an outline of the straight-ahead support (automatic straight-ahead travel) of the seedling transplanter 1 according to the embodiment. The seedling transplanter 1 according to the present embodiment includes a traveling vehicle body 2 having a pair of left and right front wheels 4 and rear wheels 5, respectively, and a seedling planting unit 50 connected to the rear portion thereof.

[0011] In the present embodiment, the straight-ahead support refers to a function of assisting the automatic straight-ahead travel (automatic travel) of the seedling transplanter 1 in the field F by controlling the operation of the steering wheels based on the steering angle (cutting angle) of the steering wheels of the seedling transplanter 1 and the position information of the seedling transplanter 1. Here, the steering angle is set as the cutting angle of the front wheels 4. However, for example, the steering angle of the steering wheel 32 (steering, see Figure 2) may be detected as the steering angle. The position information of the seedling transplanter 1 is acquired by a GNSS unit 120 (position measuring device, see Figure 8) provided on the traveling vehicle body 2. In the following description, the front-rear and left-right direction references of the seedling transplanter 1 are based on the traveling direction of the traveling vehicle body 2 as viewed from the operator's seat 28 (see Figure 2) where the operator can sit.

[0012] As shown in the figure, the seedling transplanter 1 reciprocates within a predetermined working area G in the field F and plants seedlings with a predetermined working width D. At this time, if straight-ahead support is executed, as a manual operation by the operator using the handle 32, only the turning operation performed near the headland is required. Regarding straight-ahead travel, the seedling transplanter 1 automatically travels straight along the automatic straight-ahead line L1 (straight-ahead line). In FIG. 1, the reference sign L3 indicates the turning line by the manual operation of the seedling transplanter 1 at the headland. Further, the reference sign E indicates the entry / exit point of the seedling transplanter 1 to / from the field F.

[0013] The automatic straight-ahead line L1 of the seedling transplanter 1 by straight-ahead support is substantially parallel to the reference line L2 that is a reference for performing straight-ahead support. This reference line L2 is preset within the field F in accordance with the seedling planting direction. That is, the start position and end position of straight-ahead support are used as the reference start point (hereinafter referred to as "point A") and the reference end point (hereinafter referred to as "point B") respectively, and are acquired by the travel reference registration unit 152 (see FIG. 8) provided in the seedling transplanter 1, and the line segment connecting the acquired point A and point B is registered as the reference line L2.

[0014] The automatic straight-ahead line L1 is set as a line shifted by the planting width in the seedling transplanter 1 from the reference line L2.

[0015] Hereinafter, with reference to FIG. 2, the specific configuration of the seedling transplanter 1 will be described. FIG. 2 is a side view of the seedling transplanter 1 according to the embodiment.

[0016] A seedling planting unit 50, which is a working machine, is attached to the traveling vehicle body 2 of the seedling transplanter 1 so as to be able to move up and down via a seedling planting unit lifting mechanism 40, which is a lifting device. Further, the traveling vehicle body 2 is a four-wheel drive vehicle in which a pair of left and right front wheels 4 and a pair of left and right rear wheels 5 are both driven. By rotating the handle 32, the front wheels 4 that become the steering wheels are steered, and it is possible to travel on the field F or the road between fields F.

[0017] The seedling transplanter 1 can be equipped with auxiliary wheels 5A on the rear wheels 5. Specifically, the auxiliary wheels 5A are attached to the axle 220 of the rear wheels 5 and rotate together with the rear wheels 5. The seedling transplanter 1 can attach the auxiliary wheels 5A inside the rear wheels 5, outside the rear wheels 5, or both inside and outside the rear wheels 5. That is, the seedling transplanter 1 can change the attachment position of the auxiliary wheels 5A.

[0018] Also, the traveling vehicle body 2 includes a main frame 7 disposed substantially at the center of the vehicle body, an engine 10 which is a prime mover mounted on the main frame 7, and a power transmission device 15 that transmits the power of the engine 10 to the front and rear wheels 4, 5 and the seedling planting unit 50. In this seedling transplanter 1, an internal combustion engine such as a diesel engine or a gasoline engine is used for the engine 10 which is the power source, and the generated power is used not only to move the traveling vehicle body 2 forward and backward but also to drive the seedling planting unit 50.

[0019] Also, the power transmission device 15 has a hydraulic continuously variable transmission (hereinafter referred to as "HST") 16 that shifts and outputs the driving force transmitted from the engine 10, and a power transmission unit 17 that transmits the power from the engine 10 to the HST 16.

[0020] Also, the power transmission device 15 has. That is, the driving force from the engine 10 is transmitted to the HST 16 via the transmission case 18 by the power transmission unit 17, and the power shifted by this HST 16 is transmitted to the transmission case 18. And the transmission case 18 has a sub-shifting mechanism (not shown) that switches between a high-speed mode and a low-speed mode described later, and is attached to the front part of the main frame 7.

[0021] The power transmitted from the mission case 18 to the front wheels 4 and the rear wheels 5 can be partly transmitted to the front wheels 4 via the left and right front wheel final cases 13, and the rest can be transmitted to the rear wheels 5 via the left and right rear wheel gear cases 22. Each of the left and right front wheel final cases 13 is disposed on each side of the mission case 18. The left and right front wheels 4 are connected to the left and right front wheel final cases 13 via axles 131, and such front wheel final cases 13 can be driven in response to the steering operation of the steering wheel 32 to steer the front wheels 4.

[0022] Similarly, the rear wheels 5 are connected to the left and right rear wheel gear cases 22 via axles 220. On the other hand, power is transmitted from the mission case 18 to the seedling planting unit 50 via a planting clutch 500 provided at the rear of the traveling vehicle body 2 from a work implement drive shaft (not shown). The planting clutch 500 is operated by a planting clutch motor 510 (see FIG. 8) connected to a controller 150 (see FIG. 8) which will be described in detail later.

[0023] The engine 10 is disposed at substantially the center in the left-right direction of the traveling vehicle body 2 and in a state of protruding upward from a floor step 26 on which an operator places his / her feet when boarding. The floor step 26 is provided across between the front part of the traveling vehicle body 2 and the rear part of the engine 10 and is attached to the main frame 7, and a part thereof is in a lattice shape so that mud on the shoes can be dropped onto the field F. Further, a rear step 27 which also serves as a fender for the rear wheels 5 is provided behind the floor step 26. The rear step 27 has an inclined surface inclined upward in the upward direction as it goes rearward, and is disposed on each side of the engine 10.

[0024] Further, the engine 10 protrudes upward from these floor step 26 and rear step 27, and an engine cover 11 for covering the engine 10 is disposed on the portions protruding from these steps 26, 27.

[0025] And, on the upper part of the engine cover 11, a driver's seat 28 on which an operator sits is installed, and in front of such driver's seat 28 and at the front center of the traveling vehicle body 2, an operation unit 30 is provided. Such operation unit 30 is arranged in a state of protruding upward from the floor surface of the floor step 26, and divides the front part side of the floor step 26 into left and right parts.

[0026] The operation unit 30 is provided with a steering post 315, and on the upper part of this steering post 315, a steering wheel 32 that can be steered by an operator is provided. As shown in FIG. 3, a finger cup lever 34 is provided on the steering post 315. FIG. 3 is a schematic view of the steering post 315 seen from the front. The finger cup lever 34 is operated by an operator, for example, when obtaining points A and B. The finger cup lever 34 can rotate in the vertical direction.

[0027] Also, in front of the steering post 315, as shown in FIG. 4, a monitor 33 is provided. FIG. 4 is a schematic view of the monitor 33. The monitor 33 is attached to an inverted U-shaped frame 320 as shown in FIG. 5. FIG. 5 is a schematic view of the monitor 33 and the frame 320 seen from the front. A space is provided below the monitor 33. The monitor 33 is provided such that the upper end of the display surface inclines backward. For example, the monitor 33 is provided such that the upper end of the display surface inclines 5 degrees backward with respect to the vertical direction.

[0028] The monitor 33 is attached to the frame 320 by attachment members 321 shown in FIGS. 6 and 7. FIG. 6 is a view of the attachment member 321 seen from the front side. FIG. 7 is a front perspective view of the monitor 33 attached to the frame 320. FIG. 7 is a view showing a state in which the front cover of the monitor 33 is removed.

[0029] The monitor 33 is provided so as to sandwich the frame 320 between a rear cover 33a and a front cover.

[0030] The mounting member 321 is provided inside the monitor 33. The mounting member 321 is attached to the frame 320 by the fixing portion 322 and the nut 323. A part of the fixing portion 322 is curved in a U shape, and the frame 320 is inserted into the curved portion. The nut 323 is inserted into the first hole 321a of the mounting member 321. By sandwiching the frame 302 together with the fixing portion 322, the monitor 33 is fixed to the frame 320.

[0031] The mounting member 321 is provided with a second hole 321b for attaching the front cover with a screw and a third hole 321c for attaching the rear cover 33a with a screw 324.

[0032] Further, a notch portion 321d is formed in the mounting member 321. The notch portion 321d is formed at a position corresponding to the welding bead 320a of the frame 320. Specifically, the notch portion 321d is formed behind the welding bead 320a. By forming the notch portion 321d, the welding bead 320a and the mounting member 321 do not come into contact, and the mounting member 321 can be attached to the frame 320 along the left - right direction. Therefore, the mounting member 321 is attached so as to be parallel to the axis (not shown) of the frame 320 extending in the left - right direction, and it is possible to prevent the monitor 33 from being attached to the frame 320 in an inclined manner.

[0033] Returning to FIG. 4, on the monitor 33, for example, a straight - travel support lamp 331 that lights up when the machine body performs automatic straight - travel running by straight - travel support, an A - point lamp 332, a B - point lamp 333, and a GNSS lamp 334 are arranged. Note that display lamps other than the lamps are arranged on the monitor 33. Also, the seedling transplanter 1 may have a plurality of monitors. The monitor may be a detachable tablet terminal device or the like.

[0034] On the monitor 33, when point A is acquired by operating the finger lift lever 34, the point A lamp 332 lights up. Also, when point B is acquired by operating the finger lift lever 34, the point B lamp 333 lights up. On the monitor 33, when the machine body is in a state where it can travel straight automatically, both the point A lamp 332 and the point B lamp 333 light up.

[0035] The GNSS lamp 334 has three display lamps and changes the number of lit display lamps according to the GNSS reception level. On the monitor 33, the operator is informed of the GNSS reception state by such a display mode.

[0036] Also, at a predetermined position of the control unit 30, for example, a buzzer 215 which is an example of the notification device 200 is provided (see FIG. 8).

[0037] Returning to FIG. 2, in the control unit 30, a main shift lever 81 (shift lever) and a sub-shift lever 82 (travel speed switching lever) are provided near the steering post 315. The main shift lever 81 is provided on the right side of the control unit 30, and the sub-shift lever 82 is provided below the handle 32.

[0038] The main shift lever 81 is a lever for switching the forward and backward movement and the travel output of the traveling vehicle body 2. By the operator's operation, the rotation angle of the trinion (not shown) of the HST 16 can be adjusted to adjust the speed of the traveling vehicle body 2. That is, the main shift lever 81 sets the target vehicle speed of the traveling vehicle body 2.

[0039] The sub-shift lever 82 is a lever for switching the travel mode that defines the travel speed of the traveling vehicle body 2 between a low-speed mode and a high-speed mode according to the place where it travels. The mode switching is performed by a sub-shift mechanism provided in the transmission case 18 according to the position of the sub-shift lever 82.

[0040] In addition, an openable and closable front cover 31 is provided at the front part of the control unit 30. And a center mascot 350 as an indicator member serving as an indicator for traveling is attached so as to be positioned at the center of the front end of the front cover 31. Although not shown in FIG. 2 for the sake of convenience, spare seedling carriers (not shown) are provided on the left and right sides of the front side of the traveling vehicle body 2.

[0041] The center mascot 350 is attached to the central position at the front part of the traveling vehicle body 2 and functions as a guide for the traveling direction when an operator sitting on the operator's seat 28 drives the seedling transplanter 1. Further, the center mascot 350 according to the present embodiment also functions as a notification device 200 for notifying the support status including whether the straight-ahead support can be executed or not.

[0042] The seedling transplanter 1 according to the present embodiment may use the center mascot 350 serving as the notification device 200 to notify information regarding the remaining amounts of work materials such as seedlings and fertilizers provided in the seedling planting unit 50 in addition to the status of the straight-ahead support.

[0043] Since the center mascot 350 always exists within the visual field of the operator facing forward, the operator can always grasp the status of the seedling transplanter 1 without diverting the line of sight from the front, which can greatly contribute to the improvement of safety.

[0044] In the seedling transplanter 1 according to the present embodiment, a GNSS unit 120 incorporating a reception antenna 121 (see FIG. 8) is disposed on the traveling vehicle body 2. By acquiring GNSS coordinates at predetermined time intervals with the reception antenna 121, the GNSS unit 120 can acquire position information on the earth at predetermined intervals.

[0045] The GNSS unit 120 is attached to the top of an antenna frame 124 whose base end is connected to the front end side of the traveling vehicle body 2 so as to be positioned directly above the axle 131 of the front wheel 4.

[0046] Here, the seedling planting unit 50 and other components will be described. The seedling planting unit 50 is attached to the rear part of the traveling vehicle body 2 so as to be able to move up and down via the seedling planting unit lifting mechanism 40. The seedling planting unit lifting mechanism 40 includes a lifting link device 41, and this lifting link device 41 includes a parallel link mechanism that connects the rear part of the traveling vehicle body 2 and the seedling planting unit 50. Such a parallel link mechanism has an upper link 41a and a lower link 41b, and these links 41a, 41b are rotatably connected to a link base frame 43 in the shape of a rear-view gate standing on the rear end of the main frame 7. And the other end sides of the links 41a, 41b are rotatably connected to the seedling planting unit 50. Thus, the seedling planting unit 50 is connected to the traveling vehicle body 2 so as to be able to move up and down.

[0047] Further, the seedling planting unit lifting mechanism 40 has a hydraulic lifting cylinder 44 that expands and contracts by hydraulic pressure, and the seedling planting unit 50 can be lifted and lowered by the expansion and contraction operation of the hydraulic lifting cylinder 44. The hydraulic lifting cylinder 44 is driven by the aforementioned HST 16, and by the lifting and lowering operation of the seedling planting unit lifting mechanism 40, the seedling planting unit 50 can be lifted to the non-working position or lowered to the ground working position (planting position).

[0048] Also, the seedling planting unit 50 can plant the range for planting seedlings in a plurality of sections or a plurality of rows. For example, it can be a seedling planting unit 50 for so-called six-row planting that plants seedlings in six sections.

[0049] Also, the seedling planting unit 50 includes a seedling planting device 60, a seedling placing table 51, and floats 47 (48, 49). Among these, the seedling placing table 51 is provided as a seedling placing member for loading a plurality of rows of seedlings at the rear part of the traveling vehicle body 2, has seedling placing surfaces 52 corresponding to the number of planting rows partitioned in the left-right direction of the traveling vehicle body 2, and it is possible to place seedlings with soil on each seedling placing surface 52.

[0050] The seedling planting device 60 is disposed below the seedling placing table 51 for placing seedlings, and is a device that takes seedlings from the seedling placing table 51 and plants them in the field F, and is supported by a planting support frame 55 disposed on the front side of the seedling placing table 51. The seedling planting device 60 has a planting transmission case 64 and a planting body 61. The planting body 61 is configured to be able to take seedlings from the seedling placing table 51 and plant them in the field F. The planting transmission case 64 can supply a driving force to the planting body 61.

[0051] In addition, the planting transmission case 64 is configured to be able to supply the power transmitted from the engine 10 to the seedling planting unit 50 to the planting body 61. The planting body 61 is rotatably connected to the planting transmission case 64. The planting body 61 also has a planting rod 62 that takes seedlings from the seedling placing table 51 and plants them in the field F, and a rotary case 63 that rotatably supports the planting rod 62 and is rotatably connected to the planting transmission case 64.

[0052] The rotary case 63 is internally provided with a non-uniform speed transmission mechanism (not shown) that can rotate the planting rod 62 while changing the rotation speed when rotating the planting rod 62 by the driving force transmitted from the planting transmission case 64. Thereby, when the planting body 61 rotates, the planting rod 62 can rotate while the rotation speed changes according to the rotation angle with respect to the rotary case 63.

[0053] The seedling planting devices 60 configured in this way are arranged one by one for every two rows. That is, a plurality of seedling planting devices 60 are each assigned a planting row. In addition, each planting transmission case 64 rotatably provides the planting bodies 61 for two rows. That is, two rotary cases 63 are connected to both sides in the left-right direction of the machine body to one planting transmission case 64.

[0054] In addition, the float 47 slides on the field surface for land preparation as the traveling vehicle body 2 moves, and has a center float 48 located at the center of the seedling planting unit 50 in the left-right direction of the traveling vehicle body 2 and side floats 49 located on both sides of the seedling planting unit 50 in the left-right direction.

[0055] In the center float 48 in this embodiment, a float potentiometer 154 (see FIG. 8) that functions as a hydraulic sensitivity mechanism for raising and lowering the seedling planting unit 50 in accordance with the conditions of the field F is provided. Such a float potentiometer 154 can change the width of the sensitivity for detecting the vertical movement of the center float 48.

[0056] For example, if the sensitivity is made sensitive, even a small vertical movement of the center float 48 will be detected and a detection signal will be sent to the controller 150. On the other hand, if the sensitivity is made insensitive, small vertical movements of the center float 48 will not be detected, and only vertical movements with an amplitude equal to or greater than a certain value will be detected and a detection signal will be sent to the controller 150.

[0057] In addition, a rotary tiller 67 for field preparation is provided on the front side at the lower position of the seedling planting unit 50. The rotary tiller 67 is configured to be rotatable by the output from the engine 10 transmitted through the rear wheel gear case 22, and is provided so as to be able to move up and down by a rotary tiller motor 165 (see FIG. 8) which is an electric motor.

[0058] Note that in the seedling transplanter 1 according to this embodiment, the controller 150 executes straight - line support on the condition that such a rotary tiller 67 for field preparation is in contact with the ground. That is, the straight - line support is executed only when the seedling planting operation is being performed.

[0059] In addition, on both the left and right sides of the seedling planting unit 50, line - drawing markers 68 for forming a line that serves as a guide for the traveling direction in the next planting row are provided. The line - drawing markers 68 draw a line on the field F as a mark when the seedling transplanter 1 makes a straight - line forward movement in the field F and then makes a straight - line forward movement after turning at the edge of the ridge in the field F.

[0060] Further, a fertilizer applicator 70 is mounted behind the driver's seat 28 on the traveling vehicle body 2. The fertilizer applicator 70 includes left and right storage hoppers 71 for storing fertilizer, a feeding device 72 for feeding out the fertilizer supplied from the storage hoppers 71 in set amounts, a fertilizer hose 74 which is a fertilizer application passage for supplying the fertilizer fed out by the feeding device 72 to the field F, and a blower 73 for supplying conveying air to the fertilizer hose 74.

[0061] By this blower 73, the fertilizer in the fertilizer hose 74 is transferred to the seedling planting unit 50 side. Further, the fertilizer applicator 70 has a fertilizer guide 75 through which the fertilizer is transferred by the fertilizer hose 74, and a furrow opener 76 for dropping the fertilizer transferred by the fertilizer hose 74 into a fertilizer application groove formed near the side of the seedling planting row.

[0062] FIG. 8 is a functional block diagram centered on the controller 150 of the seedling transplanter 1. The seedling transplanter 1 according to the present embodiment can control each part by electronic control, and the seedling transplanter 1 includes a controller 150 as a control device for controlling each part. This controller 150 is provided with a processing unit having a CPU (Central Processing Unit) or the like, a storage unit such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and further an input / output unit, and these are connected to each other and can transfer signals to each other. A computer program for controlling the seedling transplanter 1 is stored in the storage unit.

[0063] As shown in the drawing, various actuators and sensors for acquiring information on each part are connected to the controller 150.

[0064] To the controller 150, as actuators, for example, a throttle motor 100 for adjusting the intake air amount of the engine 10, a rotor motor 165 for raising and lowering the rotor 67 for soil preparation, and a planting clutch motor 510 for operating the planting clutch 500 are connected. Although not shown in the drawing, a trunnion drive motor for changing the rotation angle of the trunnion of the HST 16 is also connected to the controller 150.

[0065] In addition, various other sensors are connected to the controller 150, including a rudder angle sensor 130, a direction sensor 160, an inertial positioning device 170, a vehicle speed sensor 180 (rotation sensor), a seating sensor 190, and a lever sensor (not shown) that detects the operation amount of the main transmission lever 81 and the sub-transmission lever 82 in terms of tilt angle. Further, an imaging device such as a camera is connected to the controller 150.

[0066] The rudder angle sensor 130 is a sensor that detects the rudder angle when the front wheels 4, which are the steering wheels, are steered by operating the steering wheel 32. The rudder angle sensor 130 may detect the rudder angle based on the rotation angle of the feed belt of the steering wheel 32.

[0067] The direction sensor 160 is a sensor that detects the direction in which the aircraft is facing. The controller 150 can derive the actual traveling direction of the aircraft based on the value obtained from the direction sensor 160. The direction sensor 160 may be provided in the GNSS unit 120. Also, the direction may be calculated based on the position information of the traveling vehicle body 2 detected by the GNSS unit 120.

[0068] The inertial positioning device 170 includes a gyro sensor and an acceleration sensor, and a control board for controlling these is built-in. Note that the inertial positioning device 170 may be provided in the GNSS unit 120.

[0069] The inertial positioning device 170 detects to what extent the posture of the traveling vehicle body 2 is inclined with respect to the automatic straight-ahead line L1. The inertial positioning device 170 detects the inclination of the traveling vehicle body 2. The inertial positioning device 170 detects the inclination of the traveling vehicle body 2 in the front-rear direction and the left-right direction.

[0070] The seating sensor 190 is a sensor provided in the operator's seat 28 and composed of a load cell, a pressure-sensitive film sensor, etc., and can detect that the operator is seated on the operator's seat 28.

[0071] The vehicle speed sensor 180 acquires information regarding the vehicle speed of the traveling vehicle body 2. The vehicle speed sensor 180 detects the rotation of the front wheels 4 or the rear wheels 5 of the traveling vehicle body 2. For example, the vehicle speed sensor 180 detects the rotation of the rear wheels 5.

[0072] When the steering angle detected by the steering angle sensor 130 is not a value indicating that the traveling vehicle body 2 is traveling straight within an allowable range, or when the azimuth angle detected by the azimuth sensor 160 or the attitude detected by the inertial positioning device 170 is not a value indicating the straight-ahead direction, the straight-ahead support can be prohibited.

[0073] A value indicating that the steering angle is within the allowable range for the traveling vehicle body 2 to travel straight is, for example, a case where the absolute value of the steering angle (cut angle) of the front wheels 4 is 15 degrees or less. Also, after the traveling vehicle body 2 has turned, when the steering angle detected by the steering angle sensor 130 indicates a value where the traveling vehicle body 2 is not in a straight-ahead state (for example, 5 degrees), the straight-ahead support can also be prohibited.

[0074] Regarding the azimuth sensor 160 as well, an allowable range is set, and if the azimuth or attitude outside the allowable range continues for a time set by the controller 150 or more, it is determined that the vehicle is not facing the straight-ahead direction, and the straight-ahead support is prohibited.

[0075] Also, when some trouble or the like occurs and the straight-ahead support of the seedling transplanter 1 is stopped, in order to improve safety or prevent work mistakes, when restarting the straight-ahead support, control can be performed so that it is not restarted unless conditions such as the seedling planting unit 50 being lowered, the spare seedling platform being stored, and the planting clutch 500 being engaged are satisfied.

[0076] Also, to the controller 150, as a notification device 200, for example, a monitor 33 and a buzzer 215 that emits an alarm or the like are connected.

[0077] The controller 150 can notify the support status including the execution and stop of the straight - ahead support using the buzzer 215 and the monitor 33. Therefore, the operator can easily recognize whether the current forward - tilted posture of the machine body, the rudder angle and the posture of the machine body after turning the machine body are suitable for executing the straight - ahead support. Thus, for example, the operability of switching from the turning operation to the straight - ahead support can be improved. Note that the notification device 200 may be a tablet terminal device (not shown) that can be brought in from the outside.

[0078] Further, the seedling transplanter 1 includes a steering device 110 controllable by the controller 150 and a GNSS unit 120, and these are connected to the controller 150.

[0079] The steering device 110 includes a transmission mechanism (not shown) that is interlocked and connected to the steering wheel 32, and also includes a straight - ahead support mechanism 310 that applies an arbitrary rotational force to the steering wheel 32, enabling automatic steering by the controller 150. The transmission mechanism includes a steering motor 112 that rotates the steering wheel 32.

[0080] When executing the straight - ahead support, the controller 150 automatically steers the steering wheel 32 via the straight - ahead support mechanism 310 based on the position information acquired by the GNSS unit 120, thereby maintaining the traveling vehicle body 2 in the straight - ahead direction.

[0081] The GNSS unit 120 has a receiving antenna 121 that receives signals from artificial satellites used in GNSS, acquires the position information (coordinate information) of the seedling transplanter 1 on the earth, and transmits the acquired position information to the controller 150.

[0082] In addition, various switches such as a finger - up lever 34, a float potentiometer 154, an automatic - driving lever 140, a height - detection sensor 141, and an automatic - driving change - over switch 142 (traveling - mode switching unit) are connected to the controller 150.

[0083] The finger lift lever 34 receives the operator's operation regarding straight-ahead support. The finger lift lever 34 is operated by the operator when obtaining points A and B. Also, the finger lift lever 34 is operated when canceling the reference line L2.

[0084] The float potentiometer 154 is provided on the center float 48 that moves up and down following the unevenness of the field F, and senses the up and down movement of this center float 48, that is, the depth of the field F. The controller 150 raises and lowers the seedling planting unit 50 according to the sensed unevenness of the field F.

[0085] The height detection sensor 141 detects the height of the seedling planting unit 50. For example, the height detection sensor 141 is a potentiometer that detects the rotation angles of the links 41a and 41b. The height detection sensor 141 detects the height of the seedling planting unit 50 by detecting the rotation angles of the links 41a and 41b.

[0086] The automatic driving changeover switch 142 is a switch that switches whether to execute automatic driving. Specifically, the automatic driving changeover switch 142 is a switch that switches the driving mode to a manual driving mode or an automatic driving mode. The manual driving mode is a mode in which the vehicle travels by the operator's manual operation. The automatic driving mode is a mode in which automatic straight-ahead driving can be executed without the operator's manual operation.

[0087] The automatic driving lever 140 is a lever for starting automatic straight-ahead driving along the automatic straight-ahead line L1 that is substantially parallel to the reference line L2 after the traveling vehicle body 2 has turned.

[0088] When the driving mode is the automatic driving mode by the automatic driving changeover switch 142, and further when the automatic driving lever 140 is operated to "ON", automatic straight running can be started. Note that when the driving mode is the manual driving mode by the automatic driving changeover switch 142, even if the automatic driving lever 140 is operated to "ON", automatic straight running cannot be performed. Also, even when the driving mode is the automatic driving mode by the automatic driving changeover switch 142, if the automatic driving lever 140 is in the "OFF" state, automatic straight running is not executed.

[0089] The controller 150 has a travel reference registration unit 152 in which a reference line L2 is registered. In order to cause the rice transplanter 1 to perform straight-ahead support, a teaching operation is required in advance. The travel reference registration unit 152 registers, by a teaching operation, for example, a reference line L2 (see FIG. 1) for performing straight-ahead support and performing straight-ahead control.

[0090] The travel reference registration unit 152 acquires, respectively, a point A which is the start position of the straight-ahead support and a point B which is the end position, and registers a line segment connecting the acquired points A and B as the reference line L2.

[0091] By registering the reference line L2, the traveling direction when the straight-ahead support is executed and the distance for executing the straight-ahead support are registered. Note that by registering the length of the reference line L2 as the distance for executing the straight-ahead support, it is possible to notify the operator that, based on the straight-ahead distance of the traveling vehicle body 2, for example, the operator has approached a point where a turning operation is to be performed, that is, the field edge (ridge) is approaching. Note that the traveling distance of the traveling vehicle body 2 can be calculated, for example, based on the rotation speed of the rotor 67.

[0092] Next, the start process of the automatic straight running according to the embodiment will be described with reference to FIG. 9. FIG. 9 is a flowchart for explaining the start process of the automatic straight running according to the embodiment. Here, it is assumed that the traveling mode is the automatic traveling mode by the automatic traveling changeover switch 142. Also, it is assumed that the traveling vehicle body 2 is turning. For example, when turning the traveling vehicle body 2 near the ridge in the field, the turning is executed by the manual operation of the operator by operating the automatic traveling lever 140 to "off".

[0093] The controller 150 determines whether the automatic traveling lever 140 has been operated to "on" (S100). If the automatic traveling lever 140 has not been operated to "on" (S100: No), that is, if the automatic traveling lever 140 is "off", the current process ends.

[0094] When the automatic traveling lever 140 has been operated to "on" (S100: Yes), the controller 150 starts the automatic straight running (S101). That is, the controller 150 activates the automatic traveling.

[0095] Next, the controller 150 determines whether the height of the seedling planting unit 50 is equal to or greater than a predetermined height (S102). The predetermined height is a preset height and is higher than the ground working position.

[0096] When the height of the seedling planting unit 50 is equal to or greater than the predetermined height (S102: Yes), the controller 150 stops the automatic straight running (S103). That is, when the height of the seedling planting unit 50 is equal to or greater than the predetermined height, the controller 150 deactivates the automatic traveling. The controller 150, for example, sets the automatic traveling lever 140 to "off".

[0097] When the height of the seedling planting unit 50 is less than the predetermined height (S102: No), the controller 150 continues the automatic straight running (S104).

[0098] Further, after starting the automatic straight running in step S101, the controller 150 may proceed to step S102 after a predetermined time (for example, several seconds) set in advance has elapsed, or after the traveling vehicle body 2 has advanced a predetermined distance (for example, several tens of centimeters) set in advance.

[0099] The seedling transplanter 1 includes a traveling vehicle body 2, a seedling planting unit 50, a GNSS unit 120, and a controller 150. The seedling planting unit 50 is attached to the traveling vehicle body 2 and can be lifted and lowered between a ground working position and a non-working position. The GNSS unit 120 detects the position of the traveling vehicle body 2. The controller 150 automatically runs the traveling vehicle body 2 along the automatic straight line L1 based on the detected position of the traveling vehicle body 2. When an input operation for starting the automatic running is performed, the controller 150 activates the automatic running regardless of the lifting height of the seedling planting unit 50. After activating the automatic running, if it is detected that the height of the seedling planting unit 50 is equal to or higher than a predetermined height higher than the working position, the controller 150 deactivates the automatic running.

[0100] Thereby, the seedling transplanter 1 can start the automatic straight running even when the seedling planting unit 50 is in a state higher than the working position. Therefore, the seedling transplanter 1 can improve the workability when starting the automatic running.

[0101] Note that the controller 150 may stop the automatic straight running according to the position of the sub-shift lever 82. For example, after the automatic running lever 140 is operated to "on" and the automatic straight running is started, the controller 150 detects the position of the sub-shift lever 82.

[0102] When the position of the sub-shift lever 82 is in the high-speed mode, the controller 150 stops the automatic straight running. Also, when the position of the sub-shift lever 82 is in the low-speed mode, the controller 150 continues the automatic straight running.

[0103] Even when the position of the sub-speed lever 82 is in the high-speed mode, the seedling transplanter 1 can start automatic straight-ahead traveling. Therefore, the seedling transplanter 1 can improve the workability when starting automatic traveling. Note that when the position of the sub-speed lever 82 continues in the high-speed mode, the seedling transplanter 1 stops automatic straight-ahead traveling. Thereby, the seedling transplanter 1 can ensure safety and can appropriately plant seedlings in the field.

[0104] The monitor 33 can display the traveling mode and the deviation in the traveling direction in the traveling vehicle body 2. The deviation in the traveling direction is the deviation with respect to the automatic straight-ahead line L1. The controller 150 calculates the deviation in the traveling direction regardless of the traveling mode. The controller 150 calculates the deviation in the traveling direction based on the azimuth in the automatic straight-ahead line L1 and the azimuth detected by the azimuth sensor 160.

[0105] When the traveling mode is the automatic traveling mode, the controller 150 does not display the deviation in the traveling direction on the monitor 33. This is because when the traveling mode is the automatic traveling mode, the deviation in the traveling direction is corrected by automatic traveling.

[0106] When the traveling mode is the manual traveling mode, the controller 150 displays the deviation in the traveling direction on the monitor 33. Thereby, when the operator is manually driving the traveling vehicle body 2, the operator can know the deviation with respect to the automatic straight-ahead line L1.

[0107] Based on the position information detected by the GNSS unit 120, the controller 150 calculates the vehicle speed of the traveling vehicle body 2 (hereinafter sometimes referred to as the "first vehicle speed"). The vehicle speed data based on the position information acquired by the GNSS unit 120 is acquired at a predetermined sampling frequency (for example, 10 Hz). The controller 150 holds the acquired vehicle speed data for a predetermined time (for example, 310 ms). The controller 150 calculates the first vehicle speed by applying a predetermined low-pass filter (for example, a cut-off frequency of 0.33 Hz) to the held vehicle speed data. Thereby, the seedling transplanter 1 can accurately calculate the first vehicle speed of the traveling vehicle body 2.

[0108] In addition, when the target vehicle speed of the traveling vehicle body 2 by the main shift lever 81 is equal to or lower than a predetermined vehicle speed (for example, the second gear of forward), the controller 150 determines that the calculation condition of the first vehicle speed is not satisfied. Further, when the steering wheel 32 is within a predetermined straight-ahead range, specifically, when the steering angle detected by the steering angle sensor 130 is not within the allowable range for straight-ahead traveling of the traveling vehicle body 2, the controller 150 determines that the calculation condition of the first vehicle speed is not satisfied. Further, when the seedling planting unit 50 is in a non-working position, the controller 150 determines that the calculation condition of the first vehicle speed is not satisfied. Further, when the reception level by the GNSS unit 120 is a non-reception level, the controller 150 determines that the calculation condition of the first vehicle speed is not satisfied. Further, when the first vehicle speed is zero, the controller 150 determines that the calculation condition of the first vehicle speed is not satisfied.

[0109] When the controller 150 does not satisfy the calculation condition of the first vehicle speed, it discards the held vehicle speed data and sets the first vehicle speed to zero.

[0110] Also, as described above, the controller 150 detects the vehicle speed of the traveling vehicle body 2 (hereinafter, may be referred to as the "second vehicle speed") by the vehicle speed sensor 180. Specifically, the vehicle speed data based on the rotational speed acquired by the vehicle speed sensor 180 is acquired at a predetermined sampling frequency. The controller 150 holds the acquired vehicle speed data for a predetermined time. The controller 150 calculates the second vehicle speed by applying a predetermined low-pass filter (for example, cut-off frequency 0.33 Hz) to the held vehicle speed data. Thereby, the seedling transplanter 1 can accurately calculate the second vehicle speed of the traveling vehicle body 2.

[0111] Note that the controller 150 may apply the calculation condition of the first vehicle speed to the second vehicle speed.

[0112] The second vehicle speed may be the target opening degree of the HST 16 and the target vehicle speed calculated from the engine rotational speed.

[0113] The controller 150 calculates the slip ratio of the traveling vehicle body 2 using the first vehicle speed and the second vehicle speed. Specifically, the controller 150 calculates the slip ratio by dividing the value obtained by subtracting the first vehicle speed from the second vehicle speed by the second vehicle speed.

[0114] When the slip ratio is equal to or greater than a predetermined upper limit slip ratio, the controller 150 sets the slip ratio to the predetermined upper limit slip ratio. Also, when the slip ratio is equal to or less than a predetermined lower limit slip ratio, the controller 150 sets the slip ratio to the predetermined lower limit slip ratio.

[0115] The predetermined upper slip rate is a non-volatile value (e.g., 20%) stored by the controller 150. The predetermined lower slip rate is a non-volatile value (e.g., 0%) stored by the controller 150. The predetermined upper slip rate and the predetermined lower slip rate can be changed using a service tool. The inputtable value of the predetermined upper slip rate may be regulated (e.g., 10 - 50%). The inputtable value of the predetermined lower slip rate may be regulated (e.g., -50 - 10%).

[0116] When the slip rate is below the predetermined slip rate range (predetermined range), the controller 150 increases the fertilization amount in the fertilizer applicator 70 based on the slip rate. When the slip rate exceeds the predetermined slip rate range (predetermined range), the controller 150 decreases the fertilization amount in the fertilizer applicator 70 based on the slip rate. When the slip rate is within the predetermined slip rate range, no correction of the fertilization amount is performed. The predetermined slip rate range is a non-volatile value (e.g., 3%) stored by the controller 150. The predetermined slip rate range can be changed using a service tool.

[0117] Thereby, the seedling transplanter 1 can correct the fertilization amount in consideration of the slip rate and achieve uniform fertilization. When an excessive slip rate is calculated, the seedling transplanter 1 determines that the calculation of the slip rate is inappropriate or the field condition is irregular, and regulates the slip rate. The seedling transplanter 1 can regulate the correction of the fertilization amount by setting an upper limit value (predetermined upper slip rate) and a lower limit value (predetermined lower slip rate) for the slip rate.

[0118] The controller 150 performs the above-described correction of the fertilization amount every predetermined time. The predetermined time is a non-volatile value (e.g., 3 seconds) stored by the controller 150. The predetermined time can be changed using a service tool.

[0119] When the controller 150 cannot calculate the slip rate appropriately, it does not perform the correction of the fertilization amount.

[0120] When the controller 150 does not satisfy the calculation conditions for the first vehicle speed or the second vehicle speed, it sets the slip ratio to a default value (for example, 10%).

[0121] The seedling transplanter 1 may be provided with a brake plate 520 as shown in FIG. 10 and a seedling number count switch 521 in the seedling planting unit 50. FIG. 10 is a side view showing an outline of the seedling planting unit 50. The brake plate 520 is provided above the seedling number count switch 521. The brake plate 520 is provided to temporarily support the mat seedlings. The brake plate 520 supports the lower end of the mat seedlings. The brake plate 520 has a plurality of steps, for example, two steps. The brake plate 520 is provided so that the mat seedlings can climb over the brake plate 520 after the seedling feed belt 522 has operated a plurality of times.

[0122] When the seedling feed belt 522 operates and the mat seedlings are fed, the mat seedlings climb over the brake plate 520 and move downward. The seedling number count switch 521 is a switch for counting the number of mat seedlings. The seedling number count switch 521 is, for example, a switch common to the seedling decrease switch. The seedling number count switch 521 counts the number of mat seedlings by turning OFF and ON due to the joints between the mat seedlings. By temporarily supporting the mat seedlings with the brake plate 520, a gap is formed between the mat seedlings, and the seedling number count switch 521 can surely turn OFF and ON, so that the seedling transplanter 1 can accurately count the number of mat seedlings.

[0123] The seedling number count switch 521 does not count when the seedlings are above the seedling number count switch 521, and counts when the seedling number count switch 521 is not pressed.

[0124] The seedling number count switch 521 is provided so that when the switch is not pressed even after a predetermined number of seedling feed operations, it is determined that there is no remaining amount of seedlings.

[0125] The seedling feeding belt 522 is driven by an electric motor. When the mat seedlings cannot overcome the brake plate 520, the seedling feeding belt 522 is rotated upward once and then rotated downward. When the mat seedlings cannot overcome the brake plate 520, the operating speed of the electric motor may be increased. When the mat seedlings cannot overcome the brake plate 520, the feeding amount per one time of the seedling feeding belt 522 may be divided into small increments.

[0126] As shown in FIG. 11, the seedling planting unit 50 may be provided with a seedling reduction switch 530 having an independent sensor at the lower center of each row of the seedling tank. FIG. 11 is a side view showing the outline of the seedling planting unit 50. The seedling planting unit 50 is provided with a mechanism that can deploy or store a wall 532 that is driven by a motor to block the seedlings above the seedling reduction switch 530 in the seedling tank.

[0127] The walls 532 are independent for each row, and the walls 532 of each row are provided so as to move by a coaxial rotation fulcrum 533. The wall 532 is operated by one motor via a spring 534. On the opposite side of the rotation fulcrum 533, there is a portion 535 that protrudes above the seedling placing surface 52 of the seedling tank when the wall 532 is in the stored state. The wall 532 for blocking the seedlings, the rotation fulcrum 533, the portion 535 that protrudes above the seedling placing surface 52 of the seedling tank, and the seedling reduction switch 530 are provided so as to be arranged in order from above. The rotation fulcrum 533 is provided on the side closer to the wall 532 for blocking the seedlings. The portion 535 that protrudes above the seedling placing surface 52 of the seedling tank and the seedling reduction switch 530 are in the same position in the vertical direction, or the seedling reduction switch 530 is provided slightly below. The wall 532 for blocking the seedlings is provided above the seedling feeding belt 522.

[0128] When any one of the seedling reduction switches 530 of each row is turned off, the motor operates to the side for storing the wall 532, and after a certain time, the motor operates to the side for deploying the wall 532.

[0129] When any one of the seedling reduction switches 530 of each row is turned off and the wall 532 for blocking the seedlings is stored, if it turns on within a certain period of time, the seedling count is incremented by one. When any one of the seedling reduction switches 530 of each row is turned off and the wall 532 for blocking the seedlings is stored, if it does not turn on within a certain period of time, an alarm for the seedling reduction of the row is issued.

[0130] Further effects and modifications can be easily derived by those skilled in the art. For this reason, the broader aspects of the present invention are not limited to the specific details and representative embodiments presented and described as above. Therefore, various changes are possible without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Explanation of Signs

[0131] 1 Seedling transplanter (work vehicle) 2 Traveling vehicle body 4 Front wheels 5 Rear wheels 32 Handle (steering) 33 Monitor 50 Seedling planting section (working machine) 70 Fertilizer applicator 81 Main transmission lever (transmission lever) 82 Sub transmission lever (travel speed switching lever) 120 GNSS unit (position measuring device) 140 Automatic travel lever 141 Height detection sensor 142 Automatic travel switch (travel mode switching section) 150 Controller (control device) 160 Azimuth sensor 180 Vehicle speed sensor (rotation sensor)

Claims

1. A traveling vehicle body, a working machine attached to the traveling vehicle body and capable of being lifted and lowered to a predetermined working position and a predetermined non-working position, a position measuring device for detecting the position of the traveling vehicle body, and a control device for automatically driving the traveling vehicle body along a straight line based on the detected position of the traveling vehicle body. The working vehicle is provided with: The control device: When an input operation for starting the automatic driving is performed, the automatic driving is activated regardless of the lifting height of the working machine. After a predetermined time has elapsed after starting the automatic driving with the automatic driving activated, or after traveling a predetermined distance, if it is detected that the height of the working machine is equal to or higher than a predetermined height that is higher than the predetermined working position, the automatic driving is deactivated.

2. A traveling speed switching lever for switching the specified traveling speed of the traveling vehicle body between low speed and high speed. The working vehicle is provided with: The control device: When an input operation for starting the automatic driving is performed, the automatic driving is activated regardless of the operation position of the traveling speed switching lever. After activating the automatic driving, if it is detected that the operation position of the traveling speed switching lever is a position corresponding to high speed, the automatic driving is deactivated. The working vehicle according to claim 1.

3. A traveling mode switching unit for switching the traveling mode of the traveling vehicle body between an automatic traveling mode in which the automatic driving can be executed and a manual traveling mode in which the vehicle travels by the operation of an operator, and a display unit for displaying the traveling mode and capable of displaying the deviation in the traveling direction of the traveling vehicle body. The working vehicle is provided with: The control device: When the traveling mode is the automatic traveling mode, the deviation in the traveling direction is not displayed on the display unit. When the traveling mode is the manual traveling mode, the deviation in the traveling direction is displayed on the display unit. The working vehicle according to claim 1.

4. The control device: The vehicle speed data acquired at a predetermined sampling frequency by the position measuring device is held for a predetermined time, and a first vehicle speed of the traveling vehicle body is calculated by applying a predetermined low-pass filter to the held vehicle speed data. The working vehicle according to claim 1.

5. A shift lever for setting the target vehicle speed of the traveling vehicle body, and a steering wheel provided on the traveling vehicle body for adjusting the steering angle of the traveling vehicle body. The working vehicle is provided with: The control device: When at least one of the following conditions is satisfied: the target vehicle speed of the traveling vehicle body is less than or equal to a predetermined vehicle speed, the steering is not within a predetermined straight-ahead range, the working machine is in a non-working state, the reception level of the position measurement device is at a non-reception level, and the first vehicle speed is zero, it is determined that the calculation condition of the first vehicle speed is not satisfied. The work vehicle according to claim 4.

6. The control device When the calculation condition of the first vehicle speed is not satisfied by the vehicle speed data acquired by the position measurement device, discards the held vehicle speed data and sets the first vehicle speed to zero. The work vehicle according to claim 5.

7. A rotation sensor that detects the rotation of the wheels of the traveling vehicle body is provided with The control device By the rotation sensor, holds the vehicle speed data acquired at a predetermined sampling frequency for a predetermined time, and applies a predetermined low-pass filter to the held vehicle speed data to calculate the second vehicle speed of the traveling vehicle body. The work vehicle according to claim 4.

8. The control device Calculates the slip ratio of the traveling vehicle body using the first vehicle speed and the second vehicle speed. When the calculated slip ratio is greater than or equal to the upper limit slip ratio, sets the slip ratio to the upper limit slip ratio. When the calculated slip ratio is less than or equal to the lower limit slip ratio, sets the slip ratio to the lower limit slip ratio. The work vehicle according to claim 7.

9. A fertilizer application device provided on the traveling vehicle body for supplying fertilizer to the field is provided with The control device Calculates the slip ratio of the traveling vehicle body using the first vehicle speed and the second vehicle speed. When the slip ratio falls below a predetermined range, increases the fertilizer application amount in the fertilizer application device based on the slip ratio. The work vehicle according to claim 7.

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