Work vehicle

Abstract

To solve a problem with a conventional work vehicle that when convenient functions are used, the usability is not always satisfactory, and more specifically, with a work vehicle such as a conventional rice transplanter, its fertility degree measurement function for automatically adjusting a fertilizer application amount cannot always be used easily.SOLUTION: A work vehicle for transplanting seedlings to a farm field while travelling includes: a seedling planting device for planting seedlings; and a sensor for detecting electric resistance of soil between a first sensor electrode part and a second sensor electrode part for calculating a fertility degree of soil in the farm field. The first sensor electrode part and the second sensor electrode part are attached to the seedling planting device, and the seedling planting device includes a float whose bottom face is caused to come in contact with a soil surface of the soil. The first sensor electrode part and the second sensor electrode part are attached to the float bottom face.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a work vehicle such as a rice transplanter.

Background Art

[0002] In a work vehicle provided with a material transport device at the front part of a traveling vehicle body, a fertilizer application device at the rear part of the traveling vehicle body, a first field information detection member for detecting field information on the traveling vehicle body, and a control device for changing the fertilizer application amount of the fertilizer application device from the field information detected by the first field information detection member, a work vehicle having the first field information detection member provided below the material transport device 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] By the way, the inventor of the present invention considers various needs of work vehicle users and believes that the trend of continuously implementing convenient functions on work vehicles such as rice transplanters is accelerating more and more.

[0005] However, the inventor has noticed that for conventional work vehicles, the usability when using convenient functions is not always good.

[0006] More specifically, the inventor has noticed that for conventional work vehicles such as rice transplanters, for example, the fertility measurement for automatically adjusting the fertilizer application amount is not always easily available.

[0007] An object of the present invention is to provide a work vehicle that can improve usability in consideration of the above-described conventional problems.

Means for Solving the Problems

[0008] The first aspect of the present invention is a work vehicle that plants seedlings in a field while traveling, a seedling planting device for planting the seedlings, a sensor that detects the electrical resistance of the soil between a first sensor electrode part and a second sensor electrode part in order to calculate the fertility of the soil in the field, and is provided with the first sensor electrode part and the second sensor electrode part are attached to the seedling planting device, and the seedling planting device has a float whose float bottom surface is brought into contact with the soil surface of the soil, The work vehicle is characterized in that the first sensor electrode part and the second sensor electrode part are attached to the float bottom surface.

[0009] The second aspect of the present invention is that the seedling planting device has a float whose float bottom surface is brought into contact with the soil surface of the soil, and a seedling planting main body frame from which the float is suspended, The work vehicle according to claim 1, wherein the first sensor electrode part and the second sensor electrode part are attached to the seedling planting main body frame.

[0010] The third aspect of the present invention is that the seedling planting device has a furrow opener for forming a furrow on the soil surface, the first sensor electrode part and the second sensor electrode part are attached in front of the furrow opener, The work vehicle according to claim 2, wherein the first sensor electrode part and the second sensor electrode part are higher than the furrow opener bottom surface of the furrow opener.

[0011] The fourth aspect of the present invention is the work vehicle according to claim 3, wherein the first sensor electrode part and the second sensor electrode part are lower than the float bottom surface.

Effects of the Invention

[0012] According to the first aspect of the present invention, it is possible to improve usability.

[0013] According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, it is possible to further improve usability.

[0014] According to the third aspect of the present invention, in addition to the effects of the second aspect of the present invention, it is possible to reduce the burden on the operator.

[0015] According to the fourth aspect of the present invention, in addition to the effects of the third aspect of the present invention, it is possible to improve convenience.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

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Figure 12

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Figure 17

Figure 18

Figure 19

Mode for Carrying Out the Invention

[0017] Embodiments of the present invention will be described in detail with reference to the drawings.

[0018] The same applies hereinafter, but some components may not be shown in the drawings, or may be shown perspectively or omitted.

[0019] While explaining the operation of the rice transplanter according to the embodiment of the present invention, the operation control method of the work vehicle related to the present invention, which is realized by the rear controller 103 etc., will also be explained.

[0020] Such a rice transplanter is a work vehicle that plants seedlings in a field while traveling, and is a specific example of the work vehicle in the present invention.

[0021] (1) First, the configuration and operation of the rice transplanter according to the embodiment of the present invention will be specifically described.

[0022] The sensor 30 is a sensor that detects the electrical resistance of the soil between the first sensor electrode portion 31 and the second sensor electrode portion 32 in order to calculate the fertility of the soil in the field. The first sensor electrode portion 31 and the second sensor electrode portion 32 are attached to the seedling planting device 20 that plants seedlings.

[0023] For example, as shown in FIG. 1(a) which is a left side view of the rice transplanter according to the embodiment of the present invention, and FIG. 1(b) which is a plan view of the rice transplanter according to the embodiment of the present invention, in the fertility measurement by the first sensor electrode portion 31 and the second sensor electrode portion 32 as the rice transplanter float electrodes, the first sensor electrode portion 31 and the second sensor electrode portion 32 are attached at the symmetric float electrode arrangement positions P.

[0024] In a rice transplanter to which a fertilizer applicator is attached, by arranging the first sensor electrode portion 31 and the second sensor electrode portion 32 on the float 26 of the planting portion of the seedling planting device 20, the fertility of the soil can be measured. A configuration in which electrode arrangement is performed by providing a so-called slip ring on a wheel 10 such as a front wheel is likely to be expensive, but by arranging the electrodes on the float 26, the fertility of the soil in the field can be measured with a low-cost configuration.

[0025] The first sensor electrode portion 31 and the second sensor electrode portion 32 are symmetrically arranged with respect to the left-right direction so that the float 26, which is the central float of the planting portion, is sandwiched. By measuring the electrical resistance between two points of the soil sandwiched by the first sensor electrode portion 31 and the second sensor electrode portion 32, the amount of electrolyte inside the soil can be estimated.

[0026] The seedling planting device 20 has a float 26 in which the bottom surface 26f of the float is brought into contact with the soil surface of the soil. The first sensor electrode portion 31 and the second sensor electrode portion 32 are attached to the bottom surface 26f of the float.

[0027] For example, as shown in FIG. 2(a) which is a perspective view of the vicinity of the float 26 of the rice transplanter according to the embodiment of the present invention, and FIG. 2(b) which is a bottom view of the vicinity of the float 26 of the rice transplanter according to the embodiment of the present invention, the attachment states of the first sensor electrode portion 31 and the second sensor electrode portion 32 are visible from the upper surface of the side float and the bottom surface of the side float of the float 26.

[0028] The first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged at two or more locations on the bottom surface 26f of the float by being fastened to the float portion of the float 26 with bolts or the like, and are not in electrical contact with other electrodes and metal parts 102 such as a metal frame and are insulated. By such electrode insulation of the first sensor electrode portion 31 and the second sensor electrode portion 32, the electrical resistance between two points of the soil can be accurately measured while eliminating unnecessary electrical resistance.

[0029] The first sensor electrode portion 31 and the second sensor electrode portion 32 are attached to the float 26 by being co-fastened with the covering plate 101, and by utilizing the electrical conduction with the covering plate 101, a sufficient sensor electrode contact area with the soil can be ensured.

[0030] Of course, since it is important to ensure such a sensor electrode contact area, a configuration in which the covering plate 101 overlaps the first sensor electrode portion 31 and the second sensor electrode portion 32 in plan view may be adopted, or a configuration in which the soil plate 101 does not overlap the first sensor electrode portion 31 and the second sensor electrode portion 32 in plan view may be adopted.

[0031] The electrical conductivity of the soil described above is measured and recorded from the electrical resistance between two or more electrodes such as the first sensor electrode portion 31 and the second sensor electrode portion 32. Such electrical conductivity can be calculated from the surface area of the electrodes, the internal resistance of the circuit, and the detected voltage, etc.

[0032] When a system for acquiring position information by GNSS (Global Navigation Satellite System) is implemented, when the vehicle body movement distance from the most recent point where the electrical conductivity was recorded exceeds a predetermined distance, the position information is recorded together with the electrical conductivity. Since the electrical conductivity is recorded for each predetermined distance, redundant data recording is avoided.

[0033] Even when a system for acquiring position information by GNSS is implemented, when radio wave reception failure or the like occurs and position information cannot be acquired by GNSS, each time the vehicle body movement distance measured by the rear wheel rotation sensor reaches a predetermined distance, the position information is recorded together with the electrical conductivity.

[0034] When a specification without a GNSS antenna installed and a system for acquiring position information by GNSS is not implemented, a mode in which the position information is recorded together with the electrical conductivity each time the vehicle body movement distance measured by the rear wheel rotation sensor reaches a predetermined distance is also conceivable.

[0035] It is also conceivable that the measured electrical conductivity of the field is not necessarily recorded, and the amount of fertilizer applied is increased or decreased according to the measurement result. The amount of fertilizer can be adjusted according to the fertility.

[0036] It is also conceivable that the amount of fertilizer applied is increased or decreased based on criteria such as the average value and standard deviation of the electrical conductivity only when the number of electrical conductivity data exceeds a predetermined number.

[0037] Judgment on whether or not the float 26 is in contact with the ground, which is performed by a so-called float elevation angle sensor or the like, which is a float angle sensor of the center float portion, can be adopted as one of the electrical conductivity recording conditions of the first sensor electrode portion 31 and the second sensor electrode portion 32.

[0038] For example, as shown in FIG. 3, which is an explanatory diagram of the sensor 30 of the rice transplanter according to the embodiment of the present invention, in the fertilizer clogging sensor input circuit of the rear controller 103 where the sensor electrode portion of the fertilizer clogging sensor portion is diverted, almost no time delay occurs due to the diode 104 for the voltage rise from 0 volts to 5 volts, but a time delay for reducing noise occurs due to the RC circuit 105.

[0039] By arranging electrical elements by the diode 104 and the RC circuit 105 in the electrode input circuits of the first sensor electrode portion 31 and the second sensor electrode portion 32, a time delay is caused when a state change from a state with high electrical conductivity to a state with low electrical conductivity is induced. Even when momentary floating of the first sensor electrode portion 31 and the second sensor electrode portion 32 occurs due to vehicle body bounce or the like in the field, it is difficult for the electrical conductivity to immediately become zero. Such an arrangement of electrical elements is realized by effectively using the empty space of the existing fertilizer clogging sensor portion.

[0040] By alternatively adopting an arrangement of electrical elements using another diode, a mode in which such a time delay is not caused when a state change from a state with high electrical conductivity to a state with low electrical conductivity is induced can be considered. Even when a rapid passage through a location with high fertility occurs, immediate response can be made.

[0041] (2) Next, the configuration and operation of the rice transplanter according to the embodiment of the present invention will be described more specifically.

[0042] The seedling planting device 20 has a float 26 in which the bottom surface 26f of the float is brought into contact with the soil surface of the soil, and a seedling planting main body frame 21 from which the float 26 is suspended. The first sensor electrode portion 31 and the second sensor electrode portion 32 are attached to the seedling planting main body frame 21.

[0043] For example, as shown in FIG. 4 which is a left side view (part 1) near the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, in the fertility measurement by the first sensor electrode portion 31 and the second sensor electrode portion 32 as simple electrode sensors, when a large external force is applied, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 escape in a rotational direction toward the rear side of the vehicle body against the elastic force of the spring 201, thereby suppressing the occurrence of electrode plate breakage.

[0044] That is, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are configured by leaf springs, and when seedling planting is being performed, the contact of the electrode plates with the soil surface is always guaranteed. Since the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are always in contact with the soil surface in this way, not only is accurate electrical resistance measurement leading to accurate fertility calculation performed, but also the occurrence of electrode plate breakage is suppressed by utilizing the leaf spring escape accompanied by rotation.

[0045] Such a rotation fulcrum for rotation is provided above the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32. By utilizing gravity, the rotation of the electrode plates is realized by their own weight, so that the contact of the electrode plates with the soil surface is guaranteed with a cheap configuration.

[0046] For example, as shown in FIG. 5 which is a left side view (part 2) near the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, when a large external force is applied, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 escape, but since the spring 201 functions as a return spring, the return of the electrode plates to their normal positions is smoothly performed.

[0047] That is, by using a torque spring or the like, the spring 201 is inserted into the pivot points of the first sensor electrode portion 31 and the second sensor electrode portion 32. Since the generation of the electrode plate floating state caused by the planting unit bounce of the seedling planting device 20, which makes it impossible to perform electrical resistance measurement, is suppressed by the electrode plate pressing force accompanying the elastic force of the spring 201 applied toward the soil surface, the realization of accurate fertility calculation is expected.

[0048] The spring escape direction of the above-described first sensor electrode portion 31 and second sensor electrode portion 32 is toward the rear side of the vehicle body. When the vehicle body moves forward, the breakage of the electrode plate caused by the mechanical lock that is likely to occur in the specification where such a spring escape direction is toward the front side of the vehicle body is less likely to occur. When the vehicle body moves backward, since the planting unit of the seedling planting device 20 is lifted, almost no breakage of the electrode plate due to the spring escape occurs.

[0049] For example, as shown in FIGS. 6(a) and 6(b), which are left side views (parts three and four) near the float 26 of the rice transplanter according to the first modification of the embodiment of the present invention, since the lock plate 202 abuts against a so-called planting unit frame such as the seedling planting main body frame 21, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 do not rotate excessively in the rotation direction toward the front side of the vehicle body, and the return of the electrode plates to the normal position is surely performed.

[0050] That is, the lock plate 202 is attached so that the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 do not rotate toward the front side of the vehicle body by an amount of rotation exceeding the required amount of rotation. The occurrence of breakage of the electrode plate caused by the mechanical lock that may occur due to an excessive amount of rotation in the direction toward the front side of the vehicle body is suppressed.

[0051] The seedling planting device 20 has a furrow opener 27 for forming a furrow on the soil surface. The first sensor electrode portion 31 and the second sensor electrode portion 32 are attached in front of the furrow opener 27.

[0052] For example, as shown in FIG. 7 which is a left side view (part 5) near the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged in front of the furrow opener 27.

[0053] That is, in a rice transplanter configured to arrange the first sensor electrode portion 31 and the second sensor electrode portion 32 as variable fertilization type electrode sensors in the planting portion of the seedling planting device 20, compared with the furrow opener 27, the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged on the front side of the vehicle body. In a configuration where the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged on the rear side of the vehicle body compared with the furrow opener 27, the electrical resistance for imparting fertility may change due to the influence of the fertilizer to which the electrical resistance is applied, but in a configuration where the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged on the front side of the vehicle body in this way, it is difficult to change due to the influence of the fertilizer to which the electrical resistance is applied.

[0054] The first sensor electrode portion 31 and the second sensor electrode portion 32 are higher than the bottom surface 27f of the furrow opener 27.

[0055] For example, as shown in FIG. 8 which is a left side view (part 6) near the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, the positions of the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged higher than the position of the bottom surface 27f of the furrow opener.

[0056] That is, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are higher than the bottom surface 27f of the furrow opener. Even when the planting portion of the seedling planting device 20 is lowered, almost no electrode plate breakage, which is likely to occur in a specification where the electrode plate is lower than the furrow opener 27, occurs.

[0057] The first sensor electrode portion 31 and the second sensor electrode portion 32 are lower than the bottom surface 26f of the float.

[0058] For example, as shown in FIG. 9 which is a left side view (the seventh) near the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, the positions of the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged lower than the position of the float bottom surface 26f.

[0059] That is, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are lower than the float bottom surface 26f. Even when the water volume is small or the soil is hard, the electrode plate floating state that is likely to be caused in the specification where the electrode plate is higher than the float 26 hardly occurs at all, and accurate electrical resistance measurement is promoted.

[0060] The seedling planting device 20 has a leveling rotor 28 for leveling the soil surface. The first sensor electrode portion 31 and the second sensor electrode portion 32 are attached behind the leveling rotor 28.

[0061] For example, as shown in FIG. 10 which is a left side view (the eighth) near the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, the positions of the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged behind the position of the leveling by the leveling rotor 28.

[0062] That is, the positions of the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are behind the position of the soil surface where leveling has been performed by the leveling rotor 28. Since the unevenness of the soil surface is almost eliminated by the leveling by the leveling rotor 28, the electrode plate height is stably maintained.

[0063] The positions of the first sensor electrode portion 31 and the second sensor electrode portion 32 are shifted inward or outward of the vehicle body with respect to the left - right direction compared to the positions of the left and right wheels 10.

[0064] For example, as shown in FIG. 11 which is a plan view (one of them) near the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, the positions of the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are symmetric positions with respect to the left-right direction and do not depend on the number of seedling planting rows, and an arrangement that does not overlap with the wheel tracks of the wheels 10 is adopted.

[0065] That is, the electrode plates of the first sensor electrode portion 31 and the second sensor electrode portion 32 are arranged at positions that do not overlap with the wheel tracks of the left and right wheels 10 and do not depend on the number of seedling planting rows. Since the variation in the measured value of the electrical resistance caused by the mud lift that is likely to occur due to the rotation of the wheels 10 is suppressed, accurate electrical resistance measurement is promoted.

[0066] The calculation of the fertility based on the detected electrical resistance is adjusted according to the seedling planting depth at which the seedlings are planted.

[0067] For example, as shown in FIGS. 12, 13, and 14 which are explanatory diagrams (one to three) of the fertility calculation adjustment of the rice transplanter according to the first modification of the embodiment in the present invention, when the depth of the electrode plate corresponding to the soil preparation depth changes, inappropriate results in which the fertility expressed by SFV (Soil Fertility Value) changes are often obtained. Therefore, even when the depth of the electrode plate changes, if the concentration of the fertilizer is the same, the correction coefficient is adjusted so that an appropriate result in which the fertility is constant can be obtained.

[0068] That is, the correction value of the electrical resistance for providing fertility is changed according to the setting from the seedling planting depth adjustment lever member 23 for coping with various seedling planting depths. When the seedling planting depth is adjusted to increase, the electrode plate depths of the first sensor electrode portion 31 and the second sensor electrode portion 32 attached to the planting portion of the seedling planting device 20 increase, and the fertility is likely to be overestimated, so the correction coefficient is adjusted to decrease. When the seedling planting depth is adjusted to decrease, the electrode plate depths of the first sensor electrode portion 31 and the second sensor electrode portion 32 attached to the planting portion of the seedling planting device 20 decrease, and the fertility is likely to be underestimated, so the correction coefficient is adjusted to increase. When the seedling planting depth is changed, the electrode plate areas of the first sensor electrode portion 31 and the second sensor electrode portion 32 that are stabbed into the soil change. Although soil components such as the fertilizer concentration in the field hardly change without being affected by the depth, the electrical resistance for providing fertility is likely to change inappropriately due to the influence of the seedling planting depth. However, by adjusting such a correction coefficient, even if the seedling planting depth is adjusted, the electrical resistance reflecting uniform fertility can be appropriately measured.

[0069] The correction value of the electrical resistance for providing fertility is changed according to the setting from the float sensitivity adjustment dial to cope with various soil hardnesses. When the soil is hard, the electrode plate depth of the first sensor electrode part 31 and the second sensor electrode part 32 attached to the planting part of the seedling planting device 20 increases by being adjusted so that the seedling planting depth increases. Since the fertility is likely to be overestimated, the correction coefficient is adjusted to decrease. When the soil is soft, the electrode plate depth of the first sensor electrode part 31 and the second sensor electrode part 32 attached to the planting part of the seedling planting device 20 decreases by being adjusted so that the seedling planting depth decreases. Since the fertility is likely to be underestimated, the correction coefficient is adjusted to increase. By changing the seedling planting depth according to the setting from the float sensitivity adjustment dial, the electrode plate area of the first sensor electrode part 31 and the second sensor electrode part 32 that pierce into the soil changes. Although soil components such as the fertilizer concentration in the field hardly change without being affected by the depth, the electrical resistance for providing fertility is affected by the seedling planting depth and is likely to change inappropriately. However, by adjusting such a correction coefficient, even if the seedling planting depth is adjusted according to the setting from the float sensitivity adjustment dial, the electrical resistance reflecting the uniform fertility can be appropriately measured.

[0070] The arrangement positions of the first sensor electrode part 31 and the second sensor electrode part 32, which are two electrode sensors, are symmetric positions with respect to the left - right direction. Such symmetry suppresses the generation of the difference in the left - right electrical resistance for providing fertility, so the realization of accurate data measurement is expected.

[0071] The horizontal positions of the first sensor electrode part 31 and the second sensor electrode part 32 with respect to the left - right direction are set to the same width regardless of the number of seedling planting rows. Since changing the mounting width of the first sensor electrode part 31 and the second sensor electrode part 32 changes the electrical resistance, changing the mounting width depending on the number of seedling planting rows requires changing the control correction value. However, by adopting such a setting with the same width, the fertility can be controlled with the same correction value regardless of the number of seedling planting rows.

[0072] When a button is pressed or the like to start the fertility calculation using the above-described electrical resistance measurement along with the variable fertilization operation, and even though the float 26 is grounded, if the electrical resistance value or the fertility value is an abnormal value, an error display is output on a monitor or the like. Even when the user fails to check whether a normal electrical resistance measurement is being performed, the occurrence of an abnormality can be notified.

[0073] When so-called rice transplanter robot traveling is being performed and such an error display is output, the vehicle body traveling is automatically stopped by returning the state of the HST trinion opening degree of the main transmission to the neutral state. Since the vehicle body stops, the user can surely recognize the occurrence of an error.

[0074] The float 26 is suspended from the seedling planting main body frame 21 via a float suspension member 22 rotatably attached to the seedling planting main body frame 21. A seedling planting depth adjustment lever member 23 for rotating the float suspension member 22 is provided. A pin member 24 is erected on the float suspension member 22. A pin member attitude sensor 25 for detecting the attitude of the pin member 24 is attached to the seedling planting main body frame 21.

[0075] For example, as shown in FIG. 15 which is a left side view (No. 9) in the vicinity of the float 26 of the rice transplanter according to the first modification of the embodiment in the present invention, a pin member 24 for detecting the seedling planting depth by the pin member attitude sensor 25 protrudes from the float suspension member 22, which may also be called a seedling planting depth frame.

[0076] That is, the pin member attitude sensor 25 is provided near the seedling planting depth adjustment lever member 23, and the seedling planting depth is measured. The set seedling planting depth can be accurately measured.

[0077] The pin member attitude sensor 25 is provided on a round pipe member or the like at the pivot point of the float suspension member 22, and the seedling planting depth is measured. By attaching the sensor to such a pivot point, the measurement error of the seedling planting depth is suppressed.

[0078] For example, as shown in FIG. 16 which is a plan view (part two) near the float 26 of the rice transplanter according to the first modification of the embodiment of the present invention, the pin member attitude sensor 25, which may also be called a seedling planting depth sensor, is arranged near the center of the vehicle body.

[0079] That is, the pin member attitude sensor 25 is arranged near the center of the vehicle body with the left - right direction as a reference. Since the detection of the unevenness of the field by the float 26 with float sensitivity adjustment is performed near the center of the vehicle body, by avoiding the arrangement of the sensor at the left and right ends of the vehicle body where the measurement error of the seedling planting depth is likely to be caused, mechanical errors are suppressed.

[0080] The direction of the pin member 24 is upward at the rotation angle of the float suspension member 22 corresponding to a predetermined seedling planting depth.

[0081] For example, as shown in FIG. 17 which is a left side view (part ten) near the float 26 of the rice transplanter according to the first modification of the embodiment of the present invention, the direction of the pin member 24, which may also be called a seedling planting depth lever detection pin, is upward.

[0082] That is, when the lever position of the seedling planting depth adjustment lever member 23 is at the position of the predetermined seedling planting depth as the standard position, the direction of the pin member 24 is upward. Since the pin member attitude sensor 25 is arranged upward, almost no trouble caused by mud splashing adhesion, which is likely to occur in the specification where the direction of the pin member 24 is downward, occurs, and a reduction in the influence of mud is expected.

[0083] (3) Next, with reference mainly to FIGS. 18 and 19, the configuration and operation of the rice transplanter according to the embodiment of the present invention will be described in more detail.

[0084] Here, FIG. 18 is an explanatory view of the fertilizer hopper device 301 of the rice transplanter according to the second modification of the embodiment of the present invention, and FIG. 19 is an explanatory view of the fertilizer blower device 302 of the rice transplanter according to the second modification of the embodiment of the present invention.

[0085] (3a) First, with reference mainly to FIG. 18, the fertilizer hopper device 301 of the rice transplanter according to the embodiment of the present invention will be described.

[0086] In the fertilizer hopper lid fixing mechanism of the fertilizer hopper device 301, the hook portion for fixing the fertilizer hopper lid is composed of a wire rod processed into a U-shape. Both ends of the hook are inserted into the pipe, and the insertion portion brought to the central portion is removable. Even if the hook portion is damaged, due to the plug-in type specification, the replacement of the hook portion is easy.

[0087] A configuration is adopted in which the hook portion taken out from the lower fertilizer hopper body presses the fertilizer hopper lid. By using the diagonal cut of the round pipe at the rotation fulcrum portion, the hook portion is configured. It is not necessary to provide members for fixing the fertilizer hopper lid to the fertilizer hopper body on both the fertilizer hopper lid and the fertilizer hopper body. It is sufficient to provide the hook portion only on the fertilizer hopper body side without providing a fixing member on the fertilizer hopper lid side, so the configuration is simple. Since so-called fulcrum crossing in the round pipe portion is utilized, even when the position of the hook portion is the release position, the hook portion is firmly fixed so as not to move.

[0088] (3b) Next, with reference mainly to FIG. 19, the fertilizer blower device 302 of the rice transplanter according to the embodiment of the present invention will be described.

[0089] In the fertilizer blower of the fertilizer blower device 302, the power on / off of the fertilizer blower is interlocked with the fertilizer clutch of the rice transplanter. A sensor for detecting such power on / off is provided in the fertilizer clutch part. When the fertilizer clutch is on, the fertilizer blower is also turned on, and when the fertilizer clutch is off, the fertilizer blower is also turned off. By interlocking with the fertilizer clutch, when the fertilizer clutch is turned off and fertilization work is not performed, the fertilizer blower is turned off without continuing to rotate, so that wear of the blower brush is suppressed, the durability of the fertilizer blower is improved, and improvement of battery life is also expected.

[0090] (3c) Next, the variable fertilization control mechanism of the rice transplanter according to the embodiment of the present invention will be described.

[0091] Regarding the map data-linked zone, it is possible to select a zone where real-time variable fertilization is performed. By designating a zone where real-time variable fertilization is performed, it is possible to perform fertilizer reduction in a zone determined to be over-fertilized according to a user instruction, so that the occurrence of rice lodging and the like can be suppressed.

[0092] Regarding the map data-linked zone, real-time variable fertilization can be performed only in a zone where the fertilization amount is more than the standard fertilization amount. Since excessive fertilizer reduction in a zone with a small fertilization amount can be suppressed, a decrease in the yield is less likely to occur.

[0093] Regarding the map data-linked zone, real-time variable fertilization can be performed only in a zone where the fertilization amount is less than the standard fertilization amount. By further reducing fertilizer in a zone where the soil fertility is sufficient, rice lodging and the like can be more reliably suppressed, and fertilizer reduction is expected.

[0094] Regarding each of the map data-linked zones, it is possible to change the fertilizer reduction rate of real-time variable fertilization. Since a more detailed fertilization operation is performed, uniform growth of rice is expected.

[0095] Note that the program of the invention related to the present invention is a program for causing a computer to execute the operations of all or part of the steps (or processes, operations, and actions, etc.) of the work vehicle operation control method of the invention related to the present invention described above, and is a program that operates in cooperation with the computer.

[0096] Also, the recording medium of the invention related to the present invention is a recording medium that records a program for causing a computer to execute all or part of the operations of all or part of the steps (or processes, operations, and actions, etc.) of the work vehicle operation control method of the invention related to the present invention described above, and is a computer-readable recording medium in which the read program is used in cooperation with the computer.

[0097] Note that the "part of the steps (or processes, operations, and actions, etc.)" described above means one or several of those multiple steps.

[0098] Also, the "operation of the steps (or processes, operations, and actions, etc.)" described above means all or part of the operations of the steps described above.

[0099] Also, one usage form of the program of the invention related to the present invention may be a form in which it is transmitted through a transmission medium such as the Internet, light, radio waves, or sound waves, read by a computer, and operates in cooperation with the computer.

[0100] Also, as the recording medium, ROM (Read Only Memory), etc. are included.

[0101] Also, the computer is not limited to pure hardware such as a CPU (Central Processing Unit), and may include firmware, an OS (Operating System), and further peripheral devices.

[0102] Note that, as described above, the configuration of the present invention may be implemented either software-wise or hardware-wise.

Industrial Applicability

[0103] The work vehicle according to the present invention can improve usability and is useful for the purpose of being used in work vehicles such as rice transplanters.

Explanation of Signs

[0104] 10 Wheels 20 Seedling Planting Device 21 Seedling Planting Main Body Frame 22 Float Hanging Member 23 Seedling Planting Depth Adjustment Lever Member 24 Pin Member 25 Pin Member Posture Sensor 26 Float 26f Float Bottom Surface 27 Furrow Opener 27f Furrow Opener Bottom Surface 28 Land Leveling Rotor 30 Sensor 31 First Sensor Electrode Portion 32 Second Sensor Electrode Portion 101 Soil Covering Plate 102 Metal Portion 103 Rear Controller 104 Diode 105 RC Circuit 201 Spring 202 Lock Plate 301 Fertilizer Hopper Device 302 Fertilizer Blower Device P Float Electrode Arrangement Position

Claims

1. A work vehicle that plants seedlings in a field while traveling, comprising a seedling planting device for planting the seedlings, and a sensor that detects the electrical resistance of the soil between a first sensor electrode part and a second sensor electrode part in order to calculate the fertility of the soil in the field, wherein the first sensor electrode part and the second sensor electrode part are attached to the seedling planting device, and the seedling planting device has a float whose bottom surface of the float is brought into contact with the soil surface of the soil, the work vehicle, characterized in that the first sensor electrode part and the second sensor electrode part are attached to the bottom surface of the float.

2. The seedling planting device has a float whose bottom surface of the float is brought into contact with the soil surface of the soil, and a seedling planting main body frame from which the float is suspended, The work vehicle according to claim 1, characterized in that the first sensor electrode part and the second sensor electrode part are attached to the seedling planting main body frame.

3. The seedling planting device has a furrow opener for making a furrow in the soil surface, the first sensor electrode part and the second sensor electrode part are attached in front of the furrow opener, The work vehicle according to claim 2, characterized in that the first sensor electrode part and the second sensor electrode part are higher than the bottom surface of the furrow opener of the furrow opener.

4. The work vehicle according to claim 3, characterized in that the first sensor electrode part and the second sensor electrode part are lower than the bottom surface of the float.

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