JP2015084673A - Working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working vehicle, even when executing a backing operation, preventing a traveling vehicle body from starting to back until a float is separated from a field surface.SOLUTION: The working vehicle changes an output of an HST (HydroStatic Transmission) 23 according to a detection result of a control input of an HST lever 17 by an HST lever detecting lever 95, and lifts a seedling transplanting part 4 in conjunction with the backing operation of the HST lever 17 to operate an automatic lifting/lowering mechanism C. The working vehicle includes a control device 100 that has such a control configuration that, while a float inclination angle sensor 90 detects grounding of a float 55, even when the HST lever 17 is operated to the backing side, prevents the HST 23 from being output. This configuration can prevent a component of the seedling transplantation part 4 disposed at the back of a traveling vehicle body 2 from entering the mud of a field so as to prevent the mud from blocking the operation of a working device 4, thereby improving working efficiency compared with that of the prior art.

Description

  The present invention relates to a work vehicle such as a seedling transplanter equipped with a planting device for planting seedlings in a field.

  The seedling transplanting machine described in the following Patent Document 1 installs a float at the bottom of the seedling planting part at the time of planting work, leveles the field scene with this float, detects irregularities in the field, and seeds planting It is set as the structure which raises / lowers a part and makes the planting depth of a seedling constant.

  Moreover, the seedling transplanter described in the following Patent Document 2 has a configuration in which an elevating hydraulic cylinder that raises and lowers a seedling planting portion is expanded and contracted by changing the opening of a hydraulic valve.

JP 2013-105666 A JP 2012-85610 A

  In the seedling transplanting machine described in Patent Document 1, since the seedling planting part starts to rise at the same time as the reverse operation, the traveling vehicle body starts to reverse, so that the float sinks into the field before the float moves away from the field. There is a problem that large unevenness is formed in the field and the planting depth of the seedling is disturbed. In addition, the float is provided with a granule discharge port that is supplied from a granule supply device that supplies fertilizer and other granular material to the field. There is a problem that the granular material is not supplied to the field because it enters.

  In the seedling transplanter described in Patent Document 2, the raising and lowering of the seedling planting part is performed by opening control of the hydraulic valve. However, the opening control of the hydraulic valve is performed after the signal for switching the opening is output. There is a problem that a time lag until switching is likely to occur, the raising and lowering timing of the seedling planting part is delayed from the required timing, the seedling planting depth becomes too deep, and the float is embedded in the field scene.

  An object of the present invention is to provide a work vehicle that prevents the traveling vehicle body from moving backward while the float is not separated from the farm scene even when the vehicle is moved backward.

The above-described problems of the present invention are solved by the following solution means.
Invention of Claim 1 is arrange | positioned at the rear part of a traveling vehicle body (2), and works apparatus (seed planting part, sowing apparatus, etc.) (4) which performs work in a field, and the lower part of this work apparatus (4) A grounding member (float) (55, 56) arranged and grounded to a farm scene, and a lifting mechanism (including a lifting link device 3, a lifting cylinder 46, etc.) for moving the working device (4) up and down with hydraulic oil (R) A traveling operation member (HST lever) (17) for operating the traveling vehicle body (2) to move forward, backward or neutral, and an operation detection member (95) for detecting an operation amount of the traveling operation member (17). ), A hydraulic continuously variable transmission (HST) (23) that changes the output according to the operation amount of the travel operation member (17), and a grounding member inclination angle detection member that detects the grounding angle of the grounding member (55) (Float inclination angle sensor) (90) traveling In working vehicle arranged on the body (2),
The output of the hydraulic continuously variable transmission (23) is changed according to the detection result of the operation amount of the travel operation member (17) by the operation detection member (95), and interlocked with the reverse operation of the travel operation member (17). Then, the work device (4) is raised, the automatic lifting mechanism (backlift mechanism) (C) is operated, and the grounding member inclination angle detecting member (90) is detecting the grounding member (55). A work vehicle comprising a control device (100) having a control configuration that does not output the hydraulic continuously variable transmission (23) even when the traveling operation member (17) is operated in the reverse direction.

  According to the second aspect of the present invention, the electromagnetic valve (83) for adjusting the amount of hydraulic oil that operates the lifting mechanism (R) of the work device (4) and the traveling for detecting the traveling speed of the traveling vehicle body (2). When the detection member (rear wheel rotation sensor, GPS, etc.) (96) and the travel operation member (17) are moved forward and backward, and when the lift mechanism (R) is moved up and down, the travel detection member ( 96), when the traveling speed of the traveling vehicle body (2) is not detected, the control device (100) reduces the opening of the electromagnetic valve (83) and feeds the hydraulic oil to the lifting mechanism (R). The work vehicle according to claim 1, further comprising a control configuration that reduces the amount of the work vehicle.

  According to the third aspect of the present invention, when the automatic elevating mechanism (C) is activated when the grounding member inclination angle detecting member (90) detects the grounding of the grounding member (float) (55) to the field, the control is performed. The device (100) has a control configuration in which the opening of the hydraulic valve (83) that operates the lifting mechanism (R) of the work device (4) is widened to increase the amount of hydraulic oil supplied to the lifting mechanism (R). The work vehicle according to claim 1, wherein the work vehicle has a work vehicle.

  The invention according to claim 4 is provided with an elevating position detecting member (link sensor) (92) for detecting the elevating position of the elevating link device (3) constituting the elevating mechanism (R) of the work device (4). When the position detection member (92) detects that the lifting / lowering link device (3) has been raised to a predetermined position, the control device is configured to reduce the opening of the hydraulic valve (83) for operating the lifting mechanism (R). 100). The work vehicle according to any one of claims 1 to 3, wherein the work vehicle is provided at 100).

  According to the fifth aspect of the present invention, the control device (100) controls the opening / closing speed of the lifting / lowering hydraulic valve (83) of the working device (4) with the amount of electric current to raise and lower the working device (4). And a current value for controlling the raising / lowering speed of the work device (4) in a stepwise manner (eg, 0.1A until 1A is reached) every predetermined time (eg, 100 milliseconds). 5. The work vehicle according to claim 1, wherein the work vehicle has a lifting speed control configuration that outputs a lifting signal of the work device (4).

  According to the sixth aspect of the present invention, when the ground contact angle of the ground contact member (55) detected by the ground contact member tilt angle detecting member (float tilt angle sensor) (90) is close to the horizontal (that is, in the ground contact state). The control device (100) increases the current value for controlling the ascending / descending speed of the working device (4) step by step at a predetermined time, and the grounding angle of the grounding member (55) is a predetermined value. 6. The work vehicle according to claim 5, further comprising a control configuration that performs output control of a lift signal of the work device (4) that increases the current value to a maximum value when the current value is larger.

  The invention according to claim 7 is provided with an automatic accelerator mechanism (E) that increases or decreases the number of rotations of the engine (20) provided for driving the traveling vehicle body (2) when the traveling operation member (17) is operated, Even when the automatic accelerator mechanism (E) is in operation, the operation detection member (95) is capable of changing the rotation speed of the engine (20) when the operation detection member (95) detects the driving neutral position (idling state) or the low speed driving stage. The work vehicle according to any one of claims 1 to 6, further comprising a member (switch dial) (93).

  According to the eighth aspect of the present invention, when the rotational speed switching member (93) that changes the rotational speed of the engine (20) is operated to the high rotational speed side, the engine changes when the travel operation member (17) is operated ( 20) The control configuration in which the rotational speed is higher than the rotational speed of the engine (20) when the rotational speed switching member (93) is operated to a position other than the high rotational speed side, and the travel operation member (17) is positioned at the highest speed position. The control device (100) is provided with a control configuration for setting the rotation speed of the engine (20) to the maximum rotation regardless of the operation position of the rotation speed switching member (93) when operated up to ("8"). The work vehicle according to claim 7.

  According to the first aspect of the present invention, while the grounding member 55 is grounded, the work device 4 is controlled by controlling the output of the hydraulic continuously variable transmission 23 so that the traveling vehicle body 2 does not travel backward. Therefore, it is possible to prevent the mud from interfering with the operation of the working device 4 and to improve the work efficiency as compared with the prior art.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, when the supply of hydraulic oil to the hydraulic continuously variable transmission 23 is insufficient, the opening degree of the electromagnetic valve 83 is reduced. By reducing the amount of hydraulic oil supplied to the elevating mechanism R and increasing the amount of hydraulic oil discharged from the hydraulic continuously variable transmission 23, the shortage of hydraulic oil to the hydraulic continuously variable transmission 23 is compensated. The stop of traveling of the traveling vehicle body 2 and the suspension of the elevating mechanism R due to insufficient hydraulic oil to the hydraulic continuously variable transmission 23 are prevented, and the work efficiency is improved as compared with the prior art.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, when the grounding members 55, 56 are grounded when the lifting mechanism R of the working device 4 is activated, Since the hydraulic oil discharge amount can be increased by widening the opening of the hydraulic valve 83 that operates the lifting mechanism R of the work device 4, the operation of the lifting mechanism R is accelerated, and the lower portion of the work device 4 is placed in the field. Evacuates early and prevents mud deposits.

  According to the invention of claim 4, in addition to the effect of the invention of any one of claims 1 to 3, when the lifting link device 3 of the work device 4 moves to a predetermined height, the electromagnetic valve 83 is opened. By reducing the degree, the lifting / lowering link device 3 can be decelerated before it stops, so that the impact and vibration at the time of stopping the working device 4 during the lifting / lowering are prevented, and the durability is improved as compared with the prior art.

  According to the invention described in claim 5, in addition to the effect of the invention described in any one of claims 1 to 4, when the lifting signal of the work device 4 is transmitted from the control device 100, the work device (4 ), The electromagnetic valve 83 can be prevented from operating suddenly by increasing the current value for controlling the vertical speed of the work device (4) stepwise every predetermined time. Therefore, the generation of noise due to the sudden operation of the electromagnetic valve 83 and the vibration of the traveling vehicle body 2 due to the change in the position of the center of gravity of the work device 4 due to the rapid operation of the lifting mechanism R are prevented.

  According to the invention described in claim 6, in addition to the effect of the invention described in claim 5, the ground contact angle with respect to the horizontal of the ground contact member (float) 55 detected by the ground contact member tilt angle detection member (float tilt angle sensor) 90 is When the grounding member 55 has an angle at which it is determined that the grounding member 55 is substantially in contact with the field, the current value for controlling the lifting speed of the work device 4 is increased stepwise for each predetermined time, thereby operating the lifting mechanism. The hydraulic valve 83 can be prevented from operating suddenly, so that abnormal noise due to the sudden operation of the electromagnetic valve 83 and vibration of the airframe due to the change in the position of the center of gravity of the work device 4 due to the rapid operation of the lifting mechanism R can be prevented. Is prevented.

  When the grounding angle of the grounding member 55 is further increased, the rising speed of the working device 4 is increased by increasing the current value for raising and lowering the working device 4 to the maximum. The member 55 and the like can be prevented from ruining the field.

  According to the seventh aspect of the invention, in addition to the effect of the first aspect of the invention, when the travel operation member 17 is operated by the automatic accelerator mechanism E, the rotation of the engine 20 of the traveling vehicle body 2 is performed. Even in the state where the number is increased or decreased in conjunction, the engine speed at the driving neutral position or the low speed driving stage can be increased by the rotation speed switching member 93, so that when driving at low speed in places where high torque such as wet fields and Fukada is required Since it is possible to prevent the engine speed from being insufficient, the traveling vehicle body 2 can be traveled without the operator performing an operation for changing the engine speed separately, and the work efficiency is improved as compared with the prior art.

  Further, for example, when raising and lowering the seedling planting part 4 for replenishment work of seedlings, the rotation number switching member (when the operation detecting member 95 detects a traveling neutral position (idling state) or a low speed traveling stage ( An operator can lower the number of revolutions of the engine 20 by the switching dial 93, and the work efficiency is improved as compared with the prior art.

  According to the eighth aspect of the invention, in addition to the effect of the seventh aspect of the invention, when the engine speed switching member 93 is operated to the high speed side, the speed of the engine 20 is increased. In addition, since high torque can be continuously generated when working in wet fields or Fukada, it is possible to prevent the traveling vehicle body from becoming unable to move due to mud in the field, and work efficiency is improved.

  Further, when the traveling operation member 17 is operated to the maximum speed position, excessively high torque is applied to the traveling vehicle body 2 by setting the rotation speed of the engine 20 to the maximum rotation regardless of the operation position of the engine rotation speed switching member 93. Does not occur and the traveling speed does not become too fast, and stable traveling and work in the field become possible.

It is a side view of the riding type seedling transplanter of the Example of this invention. It is a top view of the riding type seedling transplanter of FIG. It is an example of the hydraulic circuit figure of the action | operation member of the riding type seedling transplanter of FIG. It is a control block diagram of the riding type seedling transplanter of FIG. It is an example of the hydraulic circuit figure of the action | operation member of the riding type seedling transplanter of FIG. It is a figure which shows the relationship between the engine speed in the case of operating an engine speed switching dial during the action | operation of the automatic accelerator mechanism of the riding type seedling transplanter of FIG. 1, and the operation amount of an HST lever. FIG. 8 is a plan view (FIG. 7A) of the wheel cap of the riding seedling transplanter of FIG. 1 and a wheel side view (FIG. 7B) when the wheel cap is attached to the front wheel. FIGS. 8A and 8B are schematic plan views of a vehicle equipped with the front wheels shown in FIG. 7, and FIG. 8A shows a case of turning right, and FIG. 8B shows a case of going straight. FIG. 9 is a partial plan view (FIG. 9A) and a side view (FIG. 9B) of the float and seedling planting device of the riding seedling transplanter of FIG. 1. FIG. 11 is a plan view of the float of the riding seedling transplanter of FIG. 1 (FIG. 10A) and a float side view of the riding seedling transplanter traveling on an inclined ground where the float rises forward.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
1 and 2 are a side view and a plan view of a riding seedling transplanter which is an embodiment of a work vehicle. In this riding type seedling transplanter 1, a seedling planting part 4 as a working device is mounted on the rear side of the traveling vehicle body 2 via a lifting link device 3 so as to be movable up and down. Hereinafter, a device represented by the seedling planting unit 4 and including a seeding device or the like may be referred to as a working device.

  The riding seedling transplanting machine 1 is a four-wheel drive vehicle including a pair of left and right front wheels 10 and 10 and a pair of left and right rear wheels 11 and 11 as drive wheels, and a transmission case 12 is disposed at the front of the fuselage. Front wheel final cases 13, 13 are provided on the left and right sides of the transmission case 12, and the left and right front wheels project outward from the respective front wheel support portions capable of changing the steering direction of the left and right front wheel final cases 13, 13. Left and right front wheels 10, 10 are respectively attached to axles (not shown).

Further, a seedling planting portion 4 is mounted on the rear side of the traveling vehicle body 2 so as to be movable up and down via a lifting link device 3, and a main body portion of the fertilizer application device 5 is provided on the upper rear portion of the traveling vehicle body 2.
Further, the front end portion of the main frame 15 is fixed to the rear portion of the transmission case 12, and a rear wheel rolling shaft (not shown) provided horizontally in the front and rear at the center of the rear end of the main frame 15 is used as a fulcrum. The rear wheel transmission cases 18 and 18 are supported in a freely rolling manner, and the rear wheels 11 and 11 are attached to rear wheel axles (not shown) protruding outward from the rear wheel transmission cases 18 and 18.

  The engine 20 is mounted on the main frame 15, and the rotational power of the engine 20 is transmitted to the transmission case 12 via a hydrostatic continuously variable transmission (HST) 23 and the like. The rotational power transmitted to the transmission case 12 is shifted by the main transmission and the auxiliary transmission in the transmission case 12 and then separated into the traveling power and the external take-out shaft.

  A part of the driving power transmitted from the engine 20 via the HST 23 drives the front wheels 10 and 10 through the front wheel final cases 13 and 13, and the rest through the rear wheel transmission cases 18 and 18 and the rear wheels 11 and 11. Drive. Further, the external take-out power is transmitted to a planting clutch case 25 provided at the rear part of the traveling vehicle body 2, and then transmitted to the seedling planting unit 4 by a planting transmission shaft 26.

  There is a control unit 33 provided with a cockpit 31 at the upper part of the engine 20, and a control lever 33 (HST operation) for operating the HST 23 to shift the vehicle body 2 forward and backward, stop, and change the travel speed. (Lever) 17 and an auxiliary transmission lever 16 for shifting the traveling speed of the traveling vehicle body 2 to a plurality of stages by changing. The control device 100 can change the output of the hydraulic continuously variable transmission (HST) 23 in accordance with the detection result of the operation detection member 95 including a potentiometer that detects the operation amount of the HST operation lever 17.

  Further, a traveling clutch pedal 91 is provided on the floor step 35, and the traveling clutch pedal 91 is depressed to engage a side clutch (not shown), and then the traveling operation lever 17 is operated forward or backward. By performing the above, the vehicle body 2 can be moved.

  A front cover 32 incorporating various operation mechanisms is provided in front of the cockpit 31, and a handle 34 for steering the front wheels 10 is provided above the front cover 32. The left and right sides of the lower end of the front cover 32 are horizontal floor steps 35. The floor step 35 is provided with a number of holes (see FIG. 2), and mud on the shoe of the worker walking through the step 35 falls to the field. The rear part on the floor step 35 is a rear step 36 that also serves as a rear wheel fender.

  Further, on both the left and right sides of the front portion of the traveling vehicle body 2, there may be provided spare seedling frames 38 (preliminary seedling mounting bases 38a, 38b, 38c) on which supplementary seedlings are placed. The preliminary seedling frames 38 are supported by the machine body. The third preliminary seedling table 38c and the second and third movable link members 39b and 39c are attached to the support frame 49, and the second preliminary seedling table 38b is supported by the second and third movable link members 39b and 39c. Further, the first and second moving link members 39a and 39b and the second preliminary seedling mounting table 38b support the first preliminary seedling mounting table 38a, and the first, second and third moving link members 39a and 39b, 39c is rotated by a rotation mechanism (switching drive device) 70 made of a motor (not shown) provided on the rotation center axis of the second moving link member 39b attached to the support frame 49, so that the first preliminary seedling is mounted. Stand 38a, second reserve seedling stand 38b, third reserve seedling stand 3 c it is possible to change the stacked state being arranged in a stepped vertically and deployed state to expand substantially the same plane before and after.

  Moreover, the raising / lowering link apparatus 3 of the seedling planting part 4 is a parallel link structure, and is provided with one upper link 40 and a pair of left and right lower links 41, 41. These links 40, 41, 41 are rotatably attached to a rear-view portal-shaped link base frame 42 erected on the rear end of the main frame 15, and a vertical link 43 is connected to the end thereof. Has been.

  A first rolling rotation shaft 44 on the traveling vehicle body side is provided below the link base frame 42, a second rolling rotation shaft 44b on the seedling planting part side is provided on the vertical link 43, and the first and first Two rolling rotation shafts 44 and 44b are connected by a connecting shaft 44c, and the seedling planting portion 4 is mounted so as to be able to roll around a second rolling shaft 44b through which the connecting shaft 44c is rotatably inserted.

  An elevating hydraulic cylinder 46 is provided between a support member fixed to the main frame 15 and a tip of a swing arm (not shown) integrally formed with the upper link 40, and the cylinder 46 is expanded and contracted hydraulically. As a result, the upper link 40 rotates up and down, and the seedling planting part 4 moves up and down while maintaining a substantially constant posture.

  In addition, the seedling platform 51 has a frame structure 65 composed of a rectangular support frame 65b and a support roller 65a that supports the whole seedling planting portion 4 in the left-right direction and the up-down direction, and is formed in the left-right direction. It is the structure which slides to.

  The seedling planting section 4 has a six-row planting structure, a transmission case 50 that also serves as a frame, a mat seedling, and a left and right reciprocating motion to supply seedlings one by one to the seedling outlets 51a,. When all the seedlings are supplied to the seedling outlet 51a, ..., the seedling mount 51 for transferring the seedling downward by the seedling feeding belt 51b, ..., seedling planting for planting the seedling supplied to the seedling outlet 51a, ... in the field A seedling planting device 52 provided with claws 52a, and a pair of left and right drawing markers 184 for drawing the course of the machine body in the next process to the topsoil surface.

  Note that a pair of left and right side markers 115, 115 are provided on both the left and right sides of the front part of the machine body, which are located above the seedlings planted on the adjacent strips and serve as a guide for the operator to run the machine body. The drawing markers 184 and 184 form a line that is used as a guideline for straight running by cutting the farm scene. However, if the soil is soft, the grooves are naturally buried over time, or the drawing markers 184 and 184 are wound up. The mud may disappear from the mud. At this time, if the side markers 115, 115 and the adjacent seedlings that have already been planted are traveled together, seedlings can be planted in accordance with the planting of the adjacent strips, so that the seedling planting direction is not disturbed. , Planting accuracy is improved.

Further, a center float 55 is provided at the center of the seedling planting portion 4, and side floats 56, 56 are provided on the left and right sides thereof.
When these floats 55, 56, 56 are grounded on the mud surface of the field, the aircraft moves forward, and the floats 55, 56, 56 slide while leveling the mud surface. Seedlings are planted by. Each float 55, 56, 56 is rotatably mounted so that the front end side moves up and down according to the unevenness of the soil surface of the field, and the vertical movement of the center float 55 is placed at the front of the center float 55 during planting work. By switching the electrohydraulic valve 83 (FIGS. 3 and 5) that controls the lifting hydraulic cylinder 46 according to the detection result, the seedling planting unit 4 is moved up and down by the float inclination angle sensor 90 provided. The seedling planting depth is always kept constant.

Here, the raising / lowering cylinder 46 etc. which raise / lower the seedling planting part 4 with hydraulic fluid, and the raising / lowering link apparatus 3 may be called raising / lowering mechanism R. FIG.
A rotor 27 (27a, 27b) which is an example of a leveling device is attached to the seedling planting unit 4. A rotor cover 28 is provided on the upper rear side of the leveling rotors 27a and 27b so that mud is not applied to the floats 55 and 56.

  The fertilizer applicator 5 feeds the granular fertilizer stored in the fertilizer hopper 60 by a certain amount by the feeding portions 61,... And applies the fertilizer to the left and right sides of the floats 55, 56, 56 with the fertilizer hoses 62,. Guide to a guide (not shown), ..., and drop into a fertilization groove formed in the vicinity of the side of the seedling planting line by a grooved body 64 (Fig. 1) provided on the front side of the fertilization guide, ... It has become. Air generated by the blower 58 driven by the blower electric motor 53 is blown into the fertilizer hose 62 via the air chamber 59 that is long in the left-right direction, and the fertilizer in the fertilizer hose 62 is forcibly conveyed by wind pressure. It has become.

  The auxiliary transmission lever 16 provided in the lower front part of the cockpit 31 is rotated along a lever guide (not shown), so that the auxiliary transmission (not shown) is operated as “road speed”, “neutral”, “planting”. It is configured to manually switch to any one of “speed”. The operation position of the sub transmission lever 16 can be detected by a sub transmission lever sensor (such as a potentiometer that detects the operation angle of the lever 16) (not shown) provided on the base side of the sub transmission lever 16.

3 and 5 show the configurations of the hydraulic circuits Y and Z of this embodiment, and FIG. 4 shows a control block diagram of this embodiment.
In the transmission case 12 that is an oil tank that stores hydraulic oil, an electrohydraulic valve 83 that raises the working device (seedling planting part) 4 by expanding and contracting the torque generator 82 and the lifting hydraulic cylinder 46 in accordance with the operation of the engine 20. An oil passage for supplying hydraulic oil to the hydraulic continuously variable transmission (HST) 23 and the lifting cylinder 46 and a main pump 86 for supplying oil to the oil passage are provided.

  The present embodiment is characterized in that an assist switching valve 84 is disposed at the most upstream portion of the oil passage for supplying oil from the oil tank 12 to the hydraulic circuits Y and Z where the torque generator 82 and the like are disposed. A filter 73, a main pump 86, and an assist switching valve 84 are arranged in this order from the oil tank 12 side of the road toward the torque generator 82.

  As shown in FIG. 5, a pressure accumulator (accumulator) 85 may be provided in the oil passage of the hydraulic circuit Z between the torque generator 82 and the assist switching valve 84. As described above, when the pressure accumulating device 85 is provided in the hydraulic circuit Z between the torque generator 82 and the assist switching valve 84, it is possible to prevent the pressure of the torque generator 82 from changing suddenly. While being able to go straight, the torque generator 82 is prevented from being damaged by hydraulic pressure.

  In this embodiment, a main pump 86 for supplying oil from the oil tank 12 is provided to the hydraulic circuits Y and Z of various drive units in accordance with the operation of the engine 20 from the oil tank 12 that stores the hydraulic oil. A torque generator (power steering) 82 that assists the force with hydraulic oil, a steering potentiometer 24 that detects the operation angle of the handle 34, an assist switching valve 84 that switches oil supply to the torque generator 82, and a predetermined time (example) 15-30 seconds) or when the maximum detected angle of the steering potentiometer 24 detected within a predetermined distance (eg, 10 to 20 m) is less than a set value (eg, less than 10 degrees), it is sent to the torque generator 82. A control device (100) having a timer function 88 for operating the assist switching valve 84 on the oil shut-off side is provided. There.

  Accordingly, when the maximum detection angle of the steering potentiometer 24 is less than the set value for the predetermined time or the predetermined distance, the oil supply from the oil tank 12 to the torque generator 82 is shut off, and the handle 34 is operated. Even if it is not, it can be determined that the vehicle can travel straight ahead, and the traveling vehicle body 2 can be prevented from moving in the left-right direction when a resistance force from the soil is applied to the front wheels 10.

  In addition, since the traveling vehicle body 2 can travel straight ahead without operating the handle 34, the operator can concentrate on other operations, so that the work efficiency and work accuracy are improved as compared with the prior art.

  When the steering potentiometer 24 detects an operation angle of a predetermined value or more (eg, 10 degrees or more) after the operation of the assist switching valve 84, the control device 100 causes the assist switching valve to send oil to the torque generator 82 by the timer function 88. By actuating 84, it can be determined that it is a place that cannot be handled by automatic straight traveling, that is, a place where the operation of the handle 34 is necessary, so that the operator can correct the traveling direction of the traveling vehicle body 2 with a light force. It becomes possible, and the labor of the worker is suppressed. Further, since the traveling direction of the traveling vehicle body 2 can be prevented from being disturbed, the working accuracy is improved as compared with the prior art.

  Further, when a predetermined time (e.g., 5 to 10 minutes) elapses after the timer switching function 88 switches the assist switching valve 84 to the side where the oil supply from the oil tank 12 is cut off, the control device 100 causes the torque generator 82 to supply the oil tank. 12, the assist switching valve 84 can be operated to the oil feeding side.

  In addition, after the assist switching valve 84 is switched, the maximum detection angle of the steering potentiometer 24 traveling for a predetermined time (for example, 15 to 30 seconds) or a predetermined distance (for example, 10 to 20 m) is less than a set value (for example, 10 degrees). Is less than 2), the control device 100 can be configured to operate the assist switching valve 84 on the side where the oil supply from the oil tank 12 to the torque generator 82 is cut off.

  By periodically supplying hydraulic oil from the oil tank 12 to the torque generator 82, the hydraulic oil in the blocked torque generator 82 leaks and the pressure decreases, and the front wheel 10 moves in the left-right direction due to soil resistance. Therefore, it is possible to continue traveling straight ahead, and work efficiency and work accuracy are improved as compared with the prior art.

  Further, since the internal pressure is maintained high by adjusting the operation of the assist switching valve 84, the torque generator 82 can be prevented from being damaged by the pressure and the sealing performance from being deteriorated, so that the durability of the torque generator 82 is improved as compared with the prior art. .

Further, the operation detection member 95 detects the operation amount of the HST lever 17 and changes the output of the hydraulic continuously variable transmission (HST) 23 according to the detection result of the operation amount of the HST lever 17 by the operation detection member 95. In addition, an automatic elevating mechanism (backlift mechanism) C that raises the seedling planting unit 4 is operated in conjunction with the reverse operation of the HST lever 17, and the float inclination sensor 90 detects the inclination angle of the float 55. While the float 55 is in contact with the ground, there is provided a control device 100 having a control configuration that does not output the hydraulic continuously variable transmission 23 even if the HST lever 17 is operated to the reverse side.
For this reason, since the traveling vehicle body 2 does not travel backward while the float 55 is in contact with the field, it is possible to prevent the constituent members of the seedling planting unit 4 from entering the mud in the field. Inhibiting the operation of the seedling planting unit 4 is prevented, and the work efficiency is improved as compared with the conventional technique.

  Further, while the float tilt angle sensor 90 detects the ground contact of the float 55, the control structure that does not output the HST (hydraulic continuously variable transmission) 23 to the reverse side even if the HST lever 17 is operated to the reverse side. Is provided in the control device 100, the following problems due to the traveling vehicle body 2 moving backward can be prevented. If mud adheres to the grooving device 64 that forms a groove in the field, which is provided at the outlet of the fertilizer hose 62, the groove cannot be formed in the field scene, and it becomes difficult for the fertilizer to penetrate into the field and the fertilizer is easily washed away. . In addition, mud soil may be clogged at the outlet of the fertilizer hose 62 and the fertilizer may not be supplied to the field.

  The traveling vehicle body 2 includes a rear wheel rotation sensor 96 as a speed sensor for detecting a traveling speed. Instead of the rear wheel rotation sensor 96, the traveling vehicle body 2 detects the traveling speed of the traveling vehicle body 2 using a GPS (not shown). Also good.

  When the elevating mechanism (including the elevating link device 3 and the elevating cylinder 46) R is moved up and down with the HST lever 17 being operated forward and backward, the vehicle body is driven by the rear wheel rotation sensor 96 or GPS. When it is detected that the vehicle 2 is not running, the control device 100 determines that the hydraulic oil continuously variable transmission (HST) 23 is insufficiently supplied with hydraulic oil (insufficiently charged), and the control device 100 determines that the seedling planting unit 4 A control configuration is provided in which the amount of hydraulic oil supplied to the lifting mechanism R is reduced by reducing the opening of the electromagnetic valve 83 of the hydraulic circuit that raises and lowers the hydraulic circuit, and the amount of hydraulic oil supplied to the HST 23 is increased.

Therefore, stoppage of traveling of the traveling vehicle body 2 and suspension of the elevating mechanism R due to lack of hydraulic oil to the HST 23 are prevented, and work efficiency is improved as compared with the prior art.
When the automatic tilting mechanism C is activated while the float tilt angle sensor 90 detects the ground contact of the floats 55 and 56 to the field, the control device 100 causes the hydraulic valve to actuate the lifting mechanism R of the seedling planting unit 4. The control device 100 is provided with a control configuration for increasing the amount of hydraulic oil supplied to the lifting mechanism R by widening the opening 83.

  Therefore, when the float 55 is grounded when the lifting mechanism R of the seedling planting section 4 is operated, the opening of the hydraulic valve 83 for operating the lifting mechanism R of the seedling planting section 4 is increased. Since the amount of oil discharged can be increased, the operation of the lifting mechanism R is accelerated, and the lower part of the seedling planting part 4 is quickly retracted from the field scene to prevent mud from adhering.

  An elevating position detecting member (link sensor) 92 for detecting the elevating position of the elevating link device 3 constituting the elevating mechanism R of the seedling planting unit 4 is provided, and the link sensor 92 is moved up to a predetermined position (near the maximum). When it is detected that 3 is raised, the control device 100 is provided with a control configuration for reducing the opening of the hydraulic valve 83 for operating the lifting mechanism R of the seedling planting unit 4.

  Therefore, when the lifting / lowering link device 3 of the seedling planting unit 4 moves to a predetermined height, the opening degree of the electromagnetic valve 83 is reduced so that the lifting / lowering link device 3 can be decelerated before it stops. The impact and vibration at the time of stopping while raising and lowering the portion 4 are prevented, and the durability is improved as compared with the prior art.

  In the present embodiment, the control device 100 electrically controls the opening / closing speed of the raising / lowering hydraulic valve 83 of the seedling planting unit 4 (by the amount of current) to control the raising / lowering speed of the seedling planting unit 4; , While increasing the current value for raising / lowering speed control of the seedling planting unit 4 in a stepwise manner (for example, 0.1 A each until reaching 1 A) by a timer function 88 (for example, 100 milliseconds) A lifting speed control configuration for outputting a lifting signal of the planting unit 4 is provided.

  When a raising / lowering signal of the seedling planting unit 4 is transmitted from the control device 100, a current value for controlling the raising / lowering speed of the seedling planting unit 4 is controlled by a control configuration in which the raising / lowering speed of the seedling planting unit 4 is controlled by the timer function 88. Since the electromagnetic valve 83 can be prevented from operating suddenly by raising it step by step every predetermined time, the generation of abnormal noise due to the sudden operation of the electromagnetic valve 83 or the seedling planting due to the rapid operation of the lifting mechanism R Vibrations of the traveling vehicle body 2 due to fluctuations in the position of the center of gravity of the appendage 4 are prevented.

  The float tilt angle sensor 90 detects the ground contact state from the ground contact angle of the float 55 with respect to the horizontal. That is, if the float 55 is inclined at a certain inclination angle, it can be understood that the float 55 is not grounded.

  If the float inclination angle sensor 90 indicates that the ground contact angle of the float 55 is close to horizontal (is in a ground contact state), the control device 100 uses the timer function 88 to gradually increase the seedling planting unit 4 every predetermined time. When raising and lowering the current value for controlling the lifting speed and the ground contact angle of the float 55 is larger than a predetermined value (for example, about 2 to 5 degrees depending on the working conditions), the seedling is raised to the maximum value. A control configuration for controlling the output of the raising / lowering signal of the appendage 4 is provided.

  When the ground contact angle of the float 55 detected by the float tilt angle sensor 90 is a minus angle, it is determined that the float 55 is substantially in contact with the field, and the timer function 88 moves the seedling planting unit 4 up and down. Since the increase of the current value for speed control is increased stepwise every predetermined time, the hydraulic valve 83 for operating the lifting mechanism can be prevented from operating suddenly. And the vibration of the traveling vehicle body 2 due to the change in the center of gravity position of the seedling planting part 4 due to the rapid operation of the lifting mechanism R are prevented.

  When the ground contact angle of the float 55 is increased, the raising / lowering speed of the seedling planting unit 4 is increased by increasing the current value for raising and lowering the seedling planting unit 4 to the maximum, and the upward retreating of the seedling planting unit 4 is fast. Therefore, it is possible to prevent the float 55 and the like from ruining the field.

  Note that the seedling transplanting machine of this embodiment includes an automatic accelerator mechanism E that automatically increases or decreases the rotational speed of the engine 20 provided for driving the traveling vehicle body 2 when the HST lever 17 is operated. .

  The automatic accelerator mechanism E is a mechanism that controls the engine speed in conjunction with the raising / lowering operation of the seedling planting unit (working device) 4 when the auto accelerator switch 72 is turned on. This is a mechanism having a function of reducing the engine speed to a specified rotational speed by the raising operation of the attaching part 4 and returning the engine speed being lowered by the lowering operation of the seedling attaching part 4 to the original rotational speed.

  Therefore, when the automatic accelerator mechanism E is provided to increase or decrease the number of rotations of the engine 20 provided for driving the traveling vehicle body 2 by operating the HST lever 17 and turning on the automatic accelerator switch, the automatic accelerator is provided. Even when the mechanism E is in operation, the engine speed switching can be manually changed when the HST lever operation position detecting member 95 detects the traveling neutral position (idling state) or the low speed traveling stage. A dial 93 is provided.

  When the engine speed at the driving neutral position or the low-speed driving stage can be increased by the rotation speed switching dial 93, even when the automatic accelerator mechanism E is operating, when driving at a low speed in a place where a high torque such as a wet paddy or a fukada is required. Insufficient engine speed can be prevented, and the traveling vehicle body 2 can be traveled without the operator having to separately change the engine speed, so that the work efficiency is improved over the prior art.

  Further, for example, when raising or lowering the seedling planting part 4 for a seedling replenishment operation, the engine is operated when the HST lever operation detecting member 95 detects a traveling neutral position (idling state) or a low-speed traveling stage. Since the rotation speed switching dial 93 allows the operator to increase the rotation speed of the engine 20, the supply speed of hydraulic oil to the lifting hydraulic cylinder 46 is increased, and the seedling replenishment position and planting of the seedling planting unit 4 are increased. Since the time required to move to the work position is shortened, the work efficiency is improved as compared with the prior art (see FIG. 6A).

  The seedling planting part is raised when replenishing seedlings and lowered during planting work. This operation is performed during low-speed traveling when approaching the end of the field to be refilled or when leaving after refilling.

  Even if the automatic accelerator mechanism E is in operation, if the rotation speed switching dial 93 that changes the rotation speed of the engine 20 is operated to the high rotation speed side, the rotation speed of the engine 20 that is fluctuated when the HST lever 17 is operated is increased. The control configuration in which the engine speed is higher than the engine speed when the engine speed switching dial 93 is operated to a position other than the engine speed side, and the HST lever 17 is operated to the highest speed position ("8" on the horizontal axis in FIG. 6). In such a case, the control device 100 is provided with a control configuration for setting the rotation speed of the engine 20 to the maximum rotation regardless of the operation position of the rotation speed switching dial 93.

  When operating the engine speed switching dial 93 to the high speed side, by increasing the speed of the engine 20, it is possible to constantly generate high torque when working in wetlands and Fukada. It is prevented that the traveling vehicle body cannot move due to mud in the field, and the work efficiency is improved.

  In addition, when the HST lever 17 is operated to the highest speed position, excessively high torque is applied to the traveling vehicle body 2 by setting the rotation speed of the engine 20 to the highest rotation regardless of the operation position of the engine rotation speed switching dial 93. It does not occur and the running speed does not become too fast, and stable running and work in the field are possible.

  FIG. 6 shows a specific example in which the engine speed switching dial 93 is operated while the automatic accelerator mechanism E is in operation. The vertical axis in FIG. 6 indicates the engine speed (rpm), and the horizontal axis indicates that the operation amount of the HST lever 17 can be changed in eight stages with the neutral position set to zero. The larger the operation amount, the larger the number. Represents. Further, the dotted line in FIG. 6 indicates the basic engine speed, and the broken line indicates the engine speed by the engine speed switching dial 93.

  6 (A) to 6 (F), when the HST lever operation detecting member 95 detects the traveling neutral position (idling state) or the low speed traveling stage, the engineer 20 The various patterns which increase / decrease the rotation speed of are shown.

  For example, in FIG. 6A, when the HST lever operation detection member 95 is detecting the traveling neutral position (idling state) or the low speed traveling stage, the engine speed change dial 93 allows the operator to rotate the engine 20 speed. Can be increased from the basic rotational speed during a predetermined number of shift stages at the start of traveling, and the work efficiency is improved as compared with the prior art.

  FIG. 6B is control used when it is necessary to exert a very strong torque from the start of traveling, such as in fields with high viscosity of Fukada or soil, and the engine speed from the basic engine speed of the engine 20 from the start of idling. This is a method in which the number is relatively large, the operation amount of the HST lever 17 is increased, and the engine speed is gradually converged to the basic speed. In addition, the moving speed of the traveling vehicle body 2 becomes unstable due to slipping or the like, and the planting interval is disturbed to reduce the planting accuracy.

  In addition, since the engine speed is kept high even when neutral, sufficient hydraulic fluid can be moved when raising and lowering the seedling planting part 4 when stopped, and the raising and lowering operation of the seedling planting part 4 can be performed quickly. Will improve.

  In FIG. 6 (C), in order to prevent the seedling transplanter from starting traveling due to the mud of the field at the start of traveling, the rotational speed of the engine 20 is rapidly increased from the basic rotational speed by the rotational speed switching dial 93 at the start of traveling. Indicates when to do. Since the rotation speed of the engine 20 significantly increases after the start of traveling, efficient traveling can be performed without losing resistance to the soil quality and depth of the field, and as the planting operation starts, the raising and lowering of the seedling planting unit 4 and hydraulic pressure are performed. Since the hydraulic oil required for the operation of the continuously variable transmission (HST) 23, the power steering mechanism and the like can be taken in and out of the electromagnetic valve 83, the operation delay or the operation stop due to insufficient hydraulic pressure is prevented.

FIG. 6D shows a change in the gear position of the HST lever 17 at full throttle.
When the engine speed is increased more than the basic engine speed from the start of running and the engine speed is still insufficient, the engine speed of the engine 20 is increased by the engine speed switching dial 93 as shown by the broken line. In this operation, even in fields with high mud viscosity or deep fields, sufficient running torque can be secured in the high speed range, so when running at high speed, the running speed decreases due to insufficient torque. The work efficiency is improved.

  FIG. 6E shows an example in which the output is higher than that shown in FIG. During normal operation, the speed of the engine 20 increases almost in proportion to the operation stage of the HST lever 17, so that fuel consumption can be suppressed. During rotation increase control, sufficient running torque can be secured at both low and high speeds. , Driving performance is improved.

  7 is a plan view (FIG. 7A) of the wheel cap 98, and a wheel cap 98 attached to the front wheel, and a plan view of the tire 99 (FIG. 7B), as shown in FIG. A semicircular cutout was provided in

  FIG. 8 is a schematic plan view of the vehicle equipped with the front wheels shown in FIG. 7. FIG. 8 (A) shows a case of turning right, and FIG. 8 (B) shows a case of going straight. Show. Since the semicircular cutout provided in the contact portion of the wheel cap 98 with the front wheel 10 is small during straight running, mud adhering to this portion does not fall on the adjacent planting strip. During turning, mud adhering to the entire surface of the foil cap 98 is pushed out to the outside of the front wheel 10 in the direction of arrow T in FIG. 8, so the mud resistance is large, but the resistance can be reduced by providing a notch.

Further, when the front wheel 10 is cleaned, mud that has entered the front wheel 10 from the semicircular cutout of the foil cap 98 can be easily washed away with water.
FIG. 9 shows a partial plan view (FIG. 9A) and a side view (FIG. 9B) of the floats 55 and 56 and the seedling planting device 52.

  When seedlings held by the seedling planting claws 52a of the seedling planting device 52 are planted in the field, the seedlings are pushed out along the seedling planting nails 52a, and the seedlings are planted in the field scene along with this operation. Immediately after being planted, the floats 55 and 56 level the field in the vicinity of the area, and the field scene in which the seedling is planted by the leveling operation is affected. In some cases, planting of the planted seedling The condition may be adversely affected.

  Therefore, as shown in FIG. 9A, the latter half of the floats 55 and 56 (the side part on the rear side of the rotation center of the seedling planting device 52 is not cut off, so that the seedlings planted in the field are not adversely affected. Can be.

  Further, as shown in the plan view of FIG. 10A, notches (corner cuts) are provided on the side surfaces of the floats 55 and 56 from the position where the tip of the seedling planting claw 52a moves most forward to the rear. By gradually narrowing the rear end portions of the floats 55 and 56, mud can enter as shown by the arrow S, and the leveling marks by the floats 55 and 56 can hardly be attached to the field scene. In particular, as shown in FIG. 10 (B), in an inclined place where the floats 55 and 56 are lifted forward, the effect of mud is increased by gradually narrowing the rear end portions of the floats 55 and 56.

  In addition, since the cover plate 71 is attached to both side surfaces of the floats 55 and 56 in front of the seedling planting position by the seedling planting claws 52a, mud that tends to flow into the notch portions in the latter half of the floats 55 and 56 is attached. There is an effect that it is returned while scooping with the earth covering plate 71. At this time, the shape of the bent portion on the side surface of the rear end portion of the cover plate 71 is symmetrical to the shape of the bent portion of the cutout portion on the side surface of the float so that the space between the rear end portion of the cover plate 71 and the side surfaces of the floats 55 and 56 Therefore, the soil covering performance by the soil covering plate 71 is improved.

DESCRIPTION OF SYMBOLS 1 Riding type seedling transplanter with fertilizer 2 Traveling vehicle body 3 Elevating link device 4 Seedling planting part 5 Fertilizer 10 Front wheel 11 Rear wheel 11a Rear wheel drive shaft 12 Mission case 13 Front wheel final case 15 Main frame 16 Sub-shift lever 17 Travel Operation (HST) lever 18 Rear wheel case 20 Engine 23 Hydrostatic continuously variable transmission (HST)
24 Steering potentiometer 25 Planting clutch case
26 Planting transmission shaft 27 (27a, 27b) Leveling rotor 28 Rotor cover 30 Engine cover 31 Pilot seat 32 Front cover (bonnet)
33 Control part 34 Handle 35 Floor step 36 Rear step 37a, 37b, 37c, 37d Mounting stay 38 Preliminary seedling frame (38a, 38b, 38c)
39a, 39b, 39c Moving link member 40 Upper link 41 Lower link 42 Link base frame 43 Vertical link 44 First rolling pivot 44a Through hole 44b Second rolling pivot 44c Connecting shaft 46 Elevating hydraulic cylinder 47 HST cylinder 48 Piston 49 Seedling frame support frame (frame)
DESCRIPTION OF SYMBOLS 50 Transmission case 51 Seedling stand 51a Seedling outlet 51b Seedling feeding belt 52 Seedling planting device 52a Seedling claw 53 Electric motor for blower 55 Center float 56 Side float 58 Blower 59 Air chamber 60 Fertilizer hopper 61 Feeding part 62 Fertilization hose 64 Groove body 65 Frame structure 65a Support roller 65b Support frame body 66 Forward hydraulic circuit 67 Reverse hydraulic circuit 69 Swash plate 70 Switching drive device 71 Cover plate 72 Auto accelerator switch 73 Filter 74 Input shaft 75 Output shaft 82 Torque Generator 83 Electrohydraulic valve 84 Assist switching valve 85 Accumulator 86 Main pump 88 Timer function 90 Float inclination angle sensor 91 Traveling clutch pedal 92 Lifting position detection link sensor 93 Engine speed switching dial 95 HST lever detection member 6 rear wheel rotation sensor 98 wheel cap 99 tire 100 controller 115 side marker 184 drawn marker A variable displacement hydraulic pump B fixed displacement hydraulic motor C automatic lifting mechanism E automatic accelerator mechanism R elevating mechanism

Claims (8)

A working device (4) disposed at a rear portion of the traveling vehicle body (2) and performing work in a field; a grounding member (55, 56) disposed at a lower portion of the working device (4) and grounded to a farm scene; A lifting mechanism (R) that moves the working device (4) up and down with hydraulic oil, a traveling operation member (17) that operates the traveling vehicle body (2) to a forward side, a backward side, or a neutral position, and the traveling operation member (17 ), An operation detecting member (95) for detecting the operation amount, a hydraulic continuously variable transmission (23) for changing the output in accordance with the operation amount of the travel operation member (17), and the contact angle of the ground member (55) In the working vehicle in which the grounding member inclination angle detecting member (90) for detecting the vehicle is disposed on the traveling vehicle body (2),
The output of the hydraulic continuously variable transmission (23) is changed according to the detection result of the operation amount of the travel operation member (17) by the operation detection member (95),
In conjunction with the reverse operation of the travel operation member (17), the work device (4) is raised to operate the automatic lifting mechanism (C),
While the grounding member inclination angle detection member (90) is detecting the grounding member (55), the hydraulic continuously variable transmission (23) is not output even if the traveling operation member (17) is operated to the reverse side. A work vehicle comprising a control device (100) having a control configuration. An electromagnetic valve (83) that adjusts the amount of hydraulic oil supplied to operate the lifting mechanism (R) of the work device (4), a travel detection member (96) that detects the travel speed of the travel vehicle body (2), and travel When the travel detection member (96) does not detect the travel speed of the travel vehicle body (2) when the operation member (17) is operated to move forward and backward and when the lift mechanism (R) is moved up and down. The control device (100) is provided with a control structure for reducing the amount of hydraulic oil fed to the elevating mechanism (R) by reducing the opening of the electromagnetic valve (83). The work vehicle as described in. If the automatic elevating mechanism (C) is activated while the grounding member inclination angle detection member (90) detects the grounding of the grounding member (55) to the field, the control device (100) causes the work device (4) to operate. The control structure of increasing the amount of hydraulic oil supplied to the elevating mechanism (R) by increasing the opening of the hydraulic valve (83) for operating the elevating mechanism (R). The work vehicle as described in. An elevating position detecting member (92) for detecting the elevating position of the elevating link device (3) constituting the elevating mechanism (R) of the working device (4);
When the elevating position detecting member (92) detects that the elevating link device (3) has moved up to a predetermined position, the control structure for restricting the opening of the hydraulic valve (83) for operating the elevating mechanism (R) is controlled. The work vehicle according to any one of claims 1 to 3, wherein the work vehicle is provided in the device (100). The control device (100) is configured to control the opening / closing speed of the working device (4) by electrically controlling the opening degree of the lifting / lowering hydraulic valve (83) of the working device (4) by an amount of current;
2. An ascending / descending speed control structure for outputting an ascending / descending signal of the working device (4) while increasing a current value for controlling the ascending / descending speed of the working device (4) step by step at a predetermined time. 5. The work vehicle according to any one of 4 above. When the ground contact angle of the ground contact member (55) detected by the ground contact member inclination angle detection member (90) is an angle close to the horizontal, the control device (100) gradually increases the work device (4) every predetermined time. Control structure for raising and lowering the current value of the working device (4) and increasing the current value to a maximum value when the grounding angle of the grounding member (55) is larger than a predetermined value. The work vehicle according to claim 5, further comprising: An automatic accelerator mechanism (E) that increases or decreases the number of rotations of the engine (20) provided for driving the traveling vehicle body (2) when the traveling operation member (17) is operated is provided,
Even when the automatic accelerator mechanism (E) is in operation, the operation detection member (95) is capable of changing the rotation speed of the engine (20) when the operation detection member (95) detects the driving neutral position (idling state) or the low speed driving stage. The work vehicle according to any one of claims 1 to 6, further comprising a member (93). When the rotational speed switching member (93) for changing the rotational speed of the engine (20) is operated to the high rotational speed side, the rotational speed of the engine (20) that is fluctuated when the travel operation member (17) is operated is rotated. A control configuration that is higher than the rotational speed of the engine (20) when the number switching member (93) is operated to a position other than the high rotational speed side;
When the travel operation member (17) is operated to the maximum speed position, the control device (100) has a control configuration for setting the rotation speed of the engine (20) to the maximum rotation regardless of the operation position of the rotation speed switching member (93). The work vehicle according to claim 7, wherein the work vehicle is provided.

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