JP5022472B2 - Working vehicle lifting mechanism - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a working device lifting structure for a work vehicle that includes a working device that can be moved up and down, such as a riding rice transplanter and an agricultural tractor, and a drive mechanism that drives the working device to move up and down.

  In a riding type rice transplanter, which is an example of a work vehicle, when the planting process ends and the aircraft reaches the shore, the operator operates the lift lever to the raised position and the seedling planting device located on the rice field (An example of a working device) is driven up, and the steering handle is operated to the right or left to turn the aircraft at the heel. When the turn at the shore is finished, the operator returns the steering handle to the straight position, operates the lifting lever to the lowered position, and drives the raised seedling planting device down to the surface to move to the next planting. Enter the process.

  In the above-mentioned riding type rice transplanter, when the steering handle is started to return to the straight-ahead position side from the state in which the steering handle is operated to the right or left (turning state) There is one that is configured so that the seedling planting device in the raised state is automatically driven down to the rice field.

According to the present invention, in the work device lifting structure of the work vehicle, when the work device in the raised state is automatically driven down to the ground as the turn ends, the timing of the work device being driven downward is varied. The purpose is to suppress.

(Constitution)
A first feature of the present invention resides in the following configuration in a working device lifting structure of a work vehicle.
A working device is provided in the machine body so that it can be moved up and down, and a driving mechanism that drives the working device to move up and down is provided.
First requirement detection value of the angle sensor for detecting a steering angle of the front wheels from the pivot of the machine body is started reaches a predetermined angle straight the steering limit side of the setting angle is set to the side from the steering limit degree and, When the second requirement that the measurement value of the distance sensor that measures the travel distance of the aircraft since the turning of the aircraft starts reaching the set distance is set, and satisfies either one of the first requirement and the second requirement, The working device in the raised state is automatically lowered to the ground.

(Constitution)
The second feature of the present invention is that the working device is provided in the machine body so as to be movable up and down, and includes a drive mechanism for driving the working device up and down.
First requirement detection value of the angle sensor for detecting a steering angle of the front wheels from the pivot of the machine body is started reaches a predetermined angle straight the steering limit side of the setting angle is set to the side from the steering limit degree and, When the second requirement that the measured value of the timer that measures the passage of time since the turning of the airframe reaches the set time is set, and either one of the first requirement and the second requirement is satisfied, the rising state The working device is automatically lowered to the ground.

(Constitution)
According to a third aspect of the present invention, the working device is provided on the machine body so as to be movable up and down, and includes a drive mechanism for driving the working device up and down.
Detection values of the angle sensor for detecting a steering angle of the front wheels from the turning of the body is started reaches from the steering limit side of the setting angle set from the steering limit of the predetermined angle straight side, and, of the aircraft When the measured value of a timer that measures the passage of time since the start of turning reaches a set time, the working device in the raised state is automatically lowered to the ground.

(Constitution)
The fourth feature of the present invention resides in the following configuration in the working device lifting structure of the work vehicle of the first feature of the present invention.
The set distance can be changed.

(Constitution)
A fifth feature of the present invention resides in the following configuration in the working device lifting structure for a work vehicle according to the second or third feature of the present invention.
The set time can be changed.

(Constitution)
A sixth feature of the present invention resides in the following configuration in any one of the working device lifting structures for work vehicles of the first to fifth features of the present invention.
The set angle can be changed to the steering limit side and the straight-ahead position side.

(Constitution)
A seventh feature of the present invention resides in the following configuration in any one of the working device lifting structures for work vehicles of the first to sixth features of the present invention.
The start of turning of the airframe is configured to be detected by the detection value of the angle sensor or the operation of the lift lever for the working device to the raised position.
(Constitution)
The eighth feature of the present invention resides in the construction of any one of the working device lifting structures for work vehicles of the first to sixth features of the present invention as follows.
Configured to detect the start of turning of the airframe by operating the lift lever for the working device to the raised position;
When the elevating lever is operated to the raised position, the clutch for transmitting power to the working device is operated to the disengagement side.
(Constitution)
A ninth feature of the present invention resides in the following configuration in any one of the working device lifting structures for work vehicles of the first to eighth features of the present invention.
A right side clutch that can transmit and shut off power to the right rear wheel, and a left side clutch that can transmit and shut off power to the left rear wheel, with the steering operation of the front wheel. The side clutch is configured to be operated to the disengagement side,
When the detected value of the angle sensor reaches the set angle from the steering limit side, the side clutch on the turning center side is operated to the transmission side.
(Constitution)
The tenth feature of the present invention resides in the following configuration in any one of the working device lifting structures for work vehicles of the first to ninth features of the present invention.
If the lifting lever for the working device is operated to the raised position while the working device in the raised state is automatically lowered to the ground, the lowering of the working device is stopped and the working device is raised. It is configured to be

Overall side view of riding rice transplanter A plan view showing the linkage state between the pitman arm and the right and left side clutches Diagram showing control system relationship The figure which shows the flow of control at the time of operating a 1st raising / lowering lever to a raise position, a neutral position, a descent position, and a planting position. The figure which shows the flow of control at the time of operating a 1st raising / lowering lever to an automatic position. The figure which shows the flow of control at the time of operating the 1st raising / lowering lever to an automatic position in 1st another form of implementation of invention. The figure which shows the flow of control at the time of operating a 1st raising / lowering lever to an automatic position in 2nd another form of implementation of invention. The figure which shows the flow of control at the time of operating a 1st raising / lowering lever to an automatic position in 2nd another form of implementation of invention.

[1]
As shown in FIG. 1, an engine 3 and a driving unit 4 are provided on a machine body supported by right and left front wheels 1 and right and left rear wheels 2 that can be steered right and left, and a rear part of the machine body. A seedling planting apparatus 6 is connected to a parallel quadruple link mechanism 5 so as to freely move up and down, and a single-acting hydraulic cylinder 7 that drives the link mechanism 5 to move up and down is provided. Rice transplanter is configured.

  As shown in FIG. 1, the seedling planting device 6 includes a seedling setting table 8 that is driven by reciprocating lateral feed at a predetermined stroke, a planting transmission case 9, and a rotating case 10 that is rotationally driven at the rear portion of the planting transmission case 9, A pair of planting claws 11 supported by the rotating case 10 and a plurality of grounding floats 12 are provided. The planting claws 11 are alternately turned from the lower part of the seedling table 8 by the rotation of the rotating case 10. The seedling is taken out and planted on the rice field G.

  As shown in FIG. 3, in all the grounding floats 12, the rear part of the grounding float 12 is supported so as to be swingable up and down around the horizontal axis P1, and the lower swing limit and the upper swinging of the grounding float 12 are supported. The movement limit is determined by a stopper (not shown). A potentiometer 14 for detecting the position of the front portion of the grounding float 12 with respect to the seedling planting device 6 is provided in the grounding float 12 at the center of the left and right. The detection value of the potentiometer 14 is from the surface G to the seedling planting device 6. The height detection value is input to the control device 15. The hydraulic cylinder 7 is provided with an electromagnetically operated control valve 13 that supplies and discharges hydraulic oil to operate the hydraulic cylinder 7 up and down, and the control valve 13 is operated by the control device 15.

  As shown in FIG. 1 and FIG. 3, the detection value of the potentiometer 14 changes when the seedling planting device 6 moves up and down with respect to the field surface G while the grounding float 12 follows the field surface G. Therefore, the detection value of the potentiometer 14 is detected. Based on the value, the control device 15 is operated by the control device 15 to expand and contract the hydraulic cylinder 7, and the seedling planting device 6 is automatically driven up and down so that the detection value of the potentiometer 14 is maintained at the set value. (Automatic lift control). Thus, the seedling planting device 6 is maintained at the set height from the surface G, and the seedling planting depth by the planting claws 11 is maintained at the set value. An upper limit sensor 24 for detecting that the link mechanism 5 has reached the mechanical upper limit position is provided, and a detection signal of the upper limit sensor 24 is input to the control device 15.

  As shown in FIGS. 1 and 3, a first elevating lever 28 is provided on the right side of the driver's seat 19, and the first elevating lever 28 is in a raised position, a neutral position, a lowered position, a planting position, and an automatic position. It is configured to be freely operable. Even if the first lifting lever 28 is operated and then released, the first lifting lever 28 is configured not to move from that position, and the operation position of the first lifting lever 28 is input to the control device 15. .

  As shown in FIGS. 1 and 3, the second elevating lever 20 that can be operated from the neutral position N, the upward position U from the neutral position N, and the downward position D from the neutral position N is provided to the right of the steering handle 18. The operation position of the second elevating lever 20 is input to the control device 15. The second elevating lever 20 is biased to the neutral position N. When the second elevating lever 20 is released from the second elevating lever 20 in the state of being operated to the raised position U and the lowered position D, the second elevating lever 20 is automatically neutralized. Return to position N.

[2]
As shown in FIGS. 1 and 2, a hydrostatic continuously variable transmission (not shown) in which the power of the engine 3 can be steplessly shifted to the forward side F and the reverse side R, and a gear transmission type auxiliary transmission. A transmission case 34 and a rear axle case 35 are transmitted to the right and left front wheels 1 via a transmission case 32 (not shown) and a front wheel differential mechanism (not shown). Is transmitted to the right and left rear wheels 2. As shown in FIGS. 1 and 3, the power of the transmission case 32 is transmitted to the seedling planting device 6 through the planting clutch 16 and the PTO shaft 36, and the planting clutch 16 is operated to the transmission side and the cutoff side. A motor 17 is provided, and the motor 17 is operated by the control device 15.

  As shown in FIGS. 1 and 3, a main transmission lever 21 is provided on the left side of the steering handle 18 so that the hydrostatic continuously variable transmission can be operated to the forward side F, the reverse side R, and the neutral position N. An electric cylinder 33 for operating the main transmission lever 21 operated on the high speed side of the forward side F to a predetermined low speed position on the forward side F is provided, and the electric cylinder 33 is operated by the control device 15.

  As shown in FIG. 2, in the rear axle case 35, the transmission shaft 34 is provided with a bevel gear 34 a, and the bevel gear 37 a of the rear axle 37 provided in the rear axle case 35 is engaged with the bevel gear 34 a of the transmission shaft 34. A cage (without a rear wheel differential mechanism (not shown)), right and left side clutches 38 are provided at both ends of the rear axle 37. As a result, the power of the transmission shaft 34 is transmitted to the right and left rear wheels 2 via the rear axle 37 and the right and left side clutches 38. The right and left side clutches 38 transmit and block power to the right and left rear wheels 2, and do not have a function of braking the right and left rear wheels 2.

[3]
As shown in FIGS. 2 and 3, a pitman arm 29 is provided that is pivoted right and left around the vertical axis P2 by the steering handle 18, and the pitman arm 29 and the right and left front wheels 1 are connected to the tie rod 30. The right and left front wheels 1 are configured to be steerable to the right and left by the steering handle 18.

  As shown in FIG. 2, a balance arm 23 is swingably supported around a vertical axis P <b> 3 at the lower part of the machine body, and a linkage rod 22 is connected to an arm 23 a fixed to the balance arm 23. The operation portion 29 a of the pitman arm 29 is provided with a long hole 29 b, and the pin 22 a of the linkage rod 22 is inserted into the long hole 29 b of the pitman arm 29. The linkage rod 25 is connected to both ends of the balance arm 23, and the pin 26 a of the operation arm 26 that operates the right and left side clutches 38 to the transmission side and the cutoff side is inserted into the elongated hole 25 a of the linkage rod 25. .

  As shown in FIG. 2, between the rectilinear position A of the pitman arm 29 and the right and left steering limits B, a right and left first set angle A1, a right and left second set angle A2, a right and left The left third setting angle A3 is set. As a result, when the pitman arm 29 (angle C) is positioned between the rectilinear position A and the third set angle A3 on the right and left, power is supplied to the right and left front wheels 1 and the right and left rear wheels 2. Has been communicated.

  As shown in FIGS. 2 and 3, the pitman arm 29 (angle C) is operated from the straight travel position A side to the right (left) steering limit B side beyond the third set angle A3 on the right (left). Then, the balance arm 23 is swung by the pitman arm 29 via the linkage rod 22, the right (left) linkage rod 25 is pulled by the balance arm 23, and the right (left) side clutch 38 is disconnected. Operated on the side. As a result, power is transmitted to the right and left front wheels 1 and the left (right) rear wheel 2 (the right (left) side clutch 38 is operated to the disengagement side, and the right (left) rear wheel 2 is operated. The aircraft turns to the right (left).

  As shown in FIGS. 2 and 3, the pitman arm 29 (angle C) is operated from the right (left) steering limit B side to the rightward (left) third set angle A3 to the straight traveling position A side. Then, the balance arm 23 is swung by the pitman arm 29 via the linkage rod 22, the right (left) linkage rod 25 is returned, and the right (left) side clutch 38 is operated to the transmission side. The As a result, the power is returned to the right and left front wheels 1 and the right and left rear wheels 2.

[4]
Next, the case where the 1st raising / lowering lever 28 is operated to a raise position, a neutral position, a descent position, and a planting position is demonstrated based on FIG.
When the first elevating lever 28 is operated to the raised position (step S1), the planting clutch 16 is operated to the cutoff side by the motor 17 (step S2), the control valve 13 is operated to the raised position (step S3), and the hydraulic pressure is increased. The seedling planting device 6 is driven up by the cylinder 7. In this case, when the upper limit sensor 24 detects that the link mechanism 5 has reached the upper limit position (step S4), the control valve 13 is operated to the neutral position and the hydraulic cylinder 7 is stopped (step S6). The attaching device 6 automatically stops at the upper limit position.

  When the first elevating lever 28 is operated to the neutral position (step S1), the planting clutch 16 is operated to the cutoff side by the motor 17 (step S5), the control valve 13 is operated to the neutral position (step S6), and the hydraulic pressure is increased. The cylinder 7 and the seedling planting device 6 stop at that position.

  When the first elevating lever 28 is operated to the lowered position (step S1), the planting clutch 16 is operated to the disengagement side by the motor 17 (step S7), and the automatic elevating control described in [1] is activated (step). S8). In this case, if the grounding float 12 is in a state of hanging from the surface G away from the surface G, it is determined that the detected value of the height from the surface G to the seedling planting device 6 is too high, and the control valve 13 is operated to the lowered position, and the seedling planting device 6 is driven downward by the hydraulic cylinder 7, so that the seedling planting device 6 appears to be continuously lowered. Thereafter, when the grounding float 12 contacts the surface G, the control valve 13 is operated and the hydraulic cylinder 7 is expanded and contracted so that the detection value of the potentiometer 14 is maintained at the set value, and the seedling planting device 6 is automatically operated. Therefore, the seedling planting device 6 apparently stops at the rice field G.

  When the first elevating lever 28 is operated to the planting position (step S1), the planting clutch 16 is operated to the transmission side by the motor 17 (step S9), and the automatic elevating control described in [1] above is activated (step S9). Step S10). Thereby, the control valve 13 is operated and the hydraulic cylinder 7 is expanded and contracted so that the detection value of the potentiometer 14 is maintained at the set value, and the seedling planting device 6 is automatically driven up and down. Thereby, the seedling planting device 6 is maintained at the set height from the surface G, and the planting operation in which the planting claws 11 plant the seedling is performed while the seedling planting depth is maintained at the set value. Done.

  As described above, by operating the first elevating lever 28 to the raised position, the neutral position, and the lowered position, the seedling planting device 6 can be raised to an arbitrary height within the range between the upper limit position of the link mechanism 5 and the rice field G. It can be stopped by driving up and down, and by operating the first lifting lever 28 to the planting position, the planting operation is performed while the planting depth of the seedling is maintained at the set value.

[5]
Next, the case where the 2nd raising / lowering lever 20 is operated in the state which operated the 1st raising / lowering lever 28 to the automatic position is demonstrated based on FIG.
In a state where the first elevating lever 28 is operated to the automatic position (step S1), for example, the seedling planting device 6 is automatically driven up and down so as to be maintained at the set height from the surface G (operation of automatic elevating control). When the second elevating lever 20 is operated to the raised position U (steps S11 and S18) in the state of the planting operation in which the planting clutch 16 is operated to the transmission side (steps S26, S27, and S28 described later), the motor 17 is operated. Thus, the planting clutch 16 is operated to the shut-off side (step S19), the automatic raising / lowering control is stopped, the control valve 13 is operated to the raised position (step S20), and the seedling planting device 6 is driven up by the hydraulic cylinder 7. The In this case, even if the second elevating lever 20 is held at the raised position U, or the second elevating lever 20 is operated to the raised position U and then to the neutral position N, the seedling planting device 6 is driven to rise. Will continue.

When the upper limit sensor 24 detects that the link mechanism 5 has reached the upper limit position (step S21), the control valve 13 is operated to the neutral position and the hydraulic cylinder 7 is stopped (step S22). Stops automatically at the upper limit position. Thus, by operating the 2nd raising / lowering lever 20 to the raise position U, the planting clutch 16 can be operated to the interruption | blocking side with the motor 17, and the seedling planting apparatus 6 can be driven to raise to an upper limit position at once.

  Next, when the second elevating lever 20 is operated to the lowered position D in the raised state of the seedling planting device 6 (steps S11 and S24 (N = 1)), the planting is performed in the same manner as in the previous item [4] and step S8 in FIG. In the state where the attached clutch 16 is operated to the disengagement side, the automatic elevation control is activated (steps S26 and S27). In a state where the automatic lifting control is activated, the seedling planting device 6 apparently descends continuously, and when the grounding float 12 contacts the surface G, the seedling planting device 6 apparently stops at the surface G. It becomes a state. In this case, even if the second elevating lever 20 is held at the lowered position D or the second elevating lever 20 is operated to the lowered position D and then to the neutral position N, the lowering of the seedling planting device 6 continues. Is done. By operating the second elevating lever 20 to the lowered position D in this way, the seedling planting device 6 can be driven to descend at a stroke until the grounding float 12 contacts the field surface G.

  As described above, when the seedling planting device 6 is in the lowered state (the state in which the automatic lifting control is activated), the second lifting lever 20 is operated to the neutral position N and then to the lowering position D again (steps S11 and S24). N = 2)), the planting clutch 16 is operated to the transmission side by the motor 17 (step S28), and the planting operation is started in the same manner as in the previous item [4] and steps S9 and S10 in FIG.

  In step S20 of FIG. 5, when the second elevating lever 20 is operated to the lowered position D before the seedling planting device 6 reaches the upper limit position while the seedling planting device 6 is being lifted, the step is performed (steps S21 and S23). Shifting to S26, S27, the ascending drive of the seedling planting device 6 is stopped, and the seedling planting device 6 is driven downward (operation of automatic elevation control). When the second elevating lever 20 is operated to the raised position U before the grounding float 12 reaches the surface G during the lowering drive of the seedling planting device 6 in step S27 of FIG. 5 (step S11), steps S18, S19, S20 are performed. , The lowering drive of the seedling planting device 6 is stopped, and the seedling planting device 6 is driven up.

[6]
Next, a description will be given of the first half of the case where the first elevating lever 28 is turned to the automatic position and the turn at the heel is performed with reference to FIG.
As shown in FIGS. 2 and 3, an angle sensor 31 that detects an angle C (steering angle of the front wheel 1) of the pitman arm 29 with respect to the straight traveling position A is provided, and a detection value of the angle sensor 31 is transmitted to the control device 15. Have been entered. A distance sensor 27 that measures the travel distance E of the airframe based on the number of revolutions of the transmission shaft 34 is provided, and the measured value of the distance sensor 27 is input to the control device 15.

  For example, in the state of planting work in which the seedling planting device 6 is automatically driven up and down so as to be maintained at a set height from the surface G (operation of automatic lifting control), and the planting clutch 16 is operated to the transmission side. (Steps S26, S27, S28) When the planting process has been completed and the aircraft has reached its heel, the pitman arm 29 is swung from the straight travel position A side to the right (left), and the pitman arm When 29 (angle C) is operated to the right (left) first set angle A1 (see the arrow in FIG. 3), it is determined that the aircraft has reached the heel and has started turning on the heel (step) S12).

As a result, a buzzer (not shown) is activated (step S15), the main transmission lever 21 is operated to a predetermined low speed position on the forward side F by the electric cylinder 33, and the hydrostatic continuously variable transmission is decelerated. (Step S16), the distance sensor 27 starts measuring the travel distance E of the aircraft (Step S17). The planting clutch 16 is operated to the shut-off side by the motor 17 (steps S18 and S19), the control valve 13 is operated to the raised position (step S20), and the seedling planting device 6 is driven up to the upper limit position by the hydraulic cylinder 7. (Steps S21 and S22).
In this case, even if the second elevating lever 20 is operated to the ascending position U before the pitman arm 29 (angle C) is operated from the straight traveling position A side to the first (left) first setting angle A1 (step S11). In the same manner, it is determined that the aircraft has reached the shore and turning on the heel has started, and the process proceeds to step S17.

  As described in [3] above, the pitman arm 29 (angle C) exceeds the right (left) first setting angle A1 side (straight advance position A side) from the right (left) third setting angle A3. When operated to the right (left) steering limit B side (see the arrow in FIG. 3), the balance arm 23 is swung by the pitman arm 29 via the linkage rod 22, and the right (left) linkage rod 25 is operated. Is pulled by the balance arm 23, and the right (left) side clutch 38 is operated to the disengagement side. As a result, the power is transmitted to the right and left front wheels 1 and the left (right) rear wheel 2 (the right (left) side clutch 38 is operated to the disengagement side, and the right (left) rear wheel 2 is operated. The aircraft turns to the right (left).

[7]
Next, the second half in the case of turning on the heel while the first elevating lever 28 is operated to the automatic position will be described with reference to FIG.
In general, in a riding type rice transplanter, the pitman arm 29 (angle C) is swung from the straight travel position A side to the right (left) steering limit B, and swivel is performed (see arrow in FIG. 3). ). When the turning at the shore ends and the pitman arm 29 (angle C) is operated from the right (left) steering limit B side to the right (left) second set angle A2 (see arrow in FIG. 3) ), It is determined that the turning at the heel has been completed (step S13).

  As described above, before the pitman arm 29 (angle C) reaches the right (left) second set angle A2 from the right (left) steering limit B side, the aircraft travel distance E reaches the set distance E1. Then (step S14), it is similarly determined that the turning at the heel has ended. The right and left third set angles A3 are mechanically determined by the long holes 29b of the pitman arm 29 as shown in FIG. On the other hand, the right and left set angles A2 are electrically set. As shown in FIG. 3, a setting dial 39 that can artificially change the right and left set angles A2 is provided on the steering handle 18. It is arranged on the right side. By operating the setting dial 39, the right and left setting angles A2 are set to be the same as the right and left setting angles A3, or the right and left setting angles A2 are set slightly to the right from the right and left setting angles A3. The left and right steering limits B can be set, and the right and left set angles A2 can be set slightly to the straight travel position A side from the right and left set angles A3.

  As described in [3] above, the pitman arm 29 (angle C) is operated from the right (left) steering limit B side to the right (left) third set angle A3 to the straight traveling position A side. Then (see the arrow in FIG. 3), the balance arm 23 is swung by the pitman arm 29 via the linkage rod 22, the right (left) linkage rod 25 is returned, and the right (left) side clutch is moved. 38 is operated to the transmission side. As a result, the power is returned to the right and left front wheels 1 and the right and left rear wheels 2.

  As described above, when it is determined that the turning at the heel has been completed (steps S13 and S14), a buzzer (not shown) is activated (step S25), and the seedlings are planted until the grounding float 12 contacts the rice field G. The attaching device 6 is driven downward (steps S26 and S27) (operation of automatic elevation control). Thereafter, when the second elevating lever 20 is operated to the neutral position N and then to the lower position D again (steps S11 and S24 (N = 2)), the planting clutch 16 is operated to the transmission side by the motor 17 ( In step S28), the planting operation is started in the same manner as in the preceding item [4] and steps S9 and S10 in FIG. 4, and the next planting process is started.

  In step S20 of FIG. 5, when the second elevating lever 20 is operated to the lowered position D before the seedling planting device 6 reaches the upper limit position while the seedling planting device 6 is being lifted, the step is performed (steps S21 and S23). Shifting to S26, S27, the ascending drive of the seedling planting device 6 is stopped, and the seedling planting device 6 is driven downward (operation of automatic elevation control). When the second elevating lever 20 is operated to the raised position U before the grounding float 12 reaches the surface G during the lowering drive of the seedling planting device 6 in step S27 of FIG. 5 (step S11), steps S18, S19, S20 are performed. , The lowering drive of the seedling planting device 6 is stopped, and the seedling planting device 6 is driven up.

[First Alternative Embodiment of the Invention]
In the above-mentioned [Embodiment of the invention], the configuration shown in FIG. 5 may be configured as shown in FIG.
As shown in FIG. 6, the distance sensor 27 (see FIG. 3) may be eliminated, and a timer (not shown) that measures the passage of time T may be provided. As a result, the pitman arm 29 (angle C) is operated from the rectilinear position A side to the right (left) first set angle A1 (step S32), or the second elevating lever 20 is operated to the raised position U. (Step S31), when it is determined that the aircraft has reached the heel and the turning at the heel has started, the measurement of the time T is started by the timer (Step S35).

Next, whether the pitman arm 29 (angle C) is operated from the right (left) steering limit B side to the right (left) second set angle A2 (step S33), or when the time T reaches the set time T1. (Step S34), it is determined that the turning at the end of the heel has been completed, a buzzer (not shown) is activated (Step S36), and the seedling planting device 6 is driven downward until the grounding float 12 contacts the surface G. (Steps S37 and S38) (operation of automatic elevation control). Steps other than steps S31 to S38 are the same as those in FIG.
In this case, a setting dial (not shown) capable of artificially changing the setting time T1 is disposed on the right side of the steering handle 18. By operating the setting dial, the setting time T1 can be made slightly longer or shorter.

[Second Embodiment of the Invention]
In the above-mentioned [Embodiment of the Invention] and [First Alternative Embodiment of the Invention], the configuration shown in FIGS. 5 and 6 may be configured as shown in FIGS.
As shown in FIGS. 7 and 8, when it is determined that the turning at the shore has ended, the pitman arm 29 (angle C) is moved from the right (left) steering limit B side to the right (left) second. When the set angle A2 is operated (steps S41 and S51) and the travel distance E of the aircraft reaches the set distance E1 (step S42) (when the time T reaches the set time T1 (step S52)) You may comprise so that it may be judged that the turning of this was complete | finished.

Thereby, a buzzer (not shown) is actuated (steps S43, S53), and the seedling planting device 6 is driven down until the grounding float 12 contacts the surface G (steps S44, S45, S54, S55) ( You may comprise so that operation of automatic raising / lowering control). Steps other than steps S41 to S45 and steps other than steps S51 to S55 are the same as those in FIGS.
In this case, in the above-described [Embodiment of the Invention], [First Alternative Embodiment of the Invention], and [Second Alternative Embodiment of the Invention], the setting distance E1 ( The set time T1) may be artificially changeable.

[Third Another Embodiment of the Invention]
In the above-mentioned [Embodiment of the invention] and [First another embodiment of the invention], steps S13 and S33 of FIGS. 5 and 6 are deleted, and the traveling distance E of the aircraft has reached the set distance E1. (Step S14) (when the time T has reached the set time T1 (step S34)), it may be determined that the turning at the end is finished.

  Conversely, in the above-mentioned [Embodiment of the invention] and [First alternative embodiment of the invention], steps S14 and S34 in FIGS. 5 and 6 are deleted, and the pitman arm 29 (angle C) is moved to the right (left). ) From the steering limit B side to the right (left) second set angle A2 (steps S13 and S33), it may be determined that the turning at the end is finished. .

  Instead of the configuration including the angle sensor 31 (see FIGS. 2 and 3) that detects the angle C of the pitman arm 29 with respect to the straight traveling position A, the following configuration may be used. In a configuration in which power is transmitted to the right and left rear wheels 2 via a rear wheel differential mechanism (not shown), a right rotation speed sensor (not shown) that independently detects the rotation speeds of the right and left rear wheels 2. (Not shown) and a left rotational speed sensor (not shown), and detects the start of turning and the end of turning at the shore by the difference between the detection values of the right and left rotational speed sensors (in a straight traveling state, The difference between the detection values of the right and left rotation speed sensors is close to zero, and the difference between the detection values of the right and left rotation speed sensors increases as the turning radius decreases).

The present invention is not only a riding type rice transplanter, but also a riding type direct sowing machine provided with a direct sowing device (working device) at the rear part of the machine body and a rotary tiller device (working device) at the rear part of the machine body so as to be raised and lowered. The present invention can also be applied to an agricultural tractor and a combine equipped with a cutting unit (working device) that can be raised and lowered at the front of the machine body.
In the case of an agricultural tractor or combine, when the working device is driven up, for example, step S19 in FIG. 5 may be deleted and the working clutch of the working device may be left on the transmission side (working device). The working clutch may be configured not to be operated to the cutoff side).

DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel 6 Working device 7 Drive mechanism 16 Clutch 20 Lifting lever 27 Distance sensor 31 Angle sensor 38 Side clutch A Side position A2 Setting angle B Steering limit E Travel distance of the machine E1 Setting distance T Time T1 Setting time U Increase Position G Ground

Claims (10)

A working device is provided in the machine body so that it can be moved up and down, and a driving mechanism that drives the working device to move up and down is provided.
First requirement detection value of the angle sensor for detecting a steering angle of the front wheels from the pivot of the machine body is started reaches a predetermined angle straight the steering limit side of the setting angle is set to the side from the steering limit degree and, When the second requirement that the measurement value of the distance sensor that measures the travel distance of the aircraft since the turning of the aircraft starts reaching the set distance is set, and satisfies either one of the first requirement and the second requirement, A working device lifting structure for a work vehicle configured such that the working device in the raised state is automatically lowered to the ground. A working device is provided in the machine body so that it can be moved up and down, and a driving mechanism that drives the working device to move up and down is provided.
First requirement detection value of the angle sensor for detecting a steering angle of the front wheels from the pivot of the machine body is started reaches a predetermined angle straight the steering limit side of the setting angle is set to the side from the steering limit degree and, When the second requirement that the measured value of the timer that measures the passage of time since the turning of the airframe reaches the set time is set, and either one of the first requirement and the second requirement is satisfied, the rising state A working device lifting structure for a work vehicle configured such that the working device is automatically lowered to the ground. A working device is provided in the machine body so that it can be moved up and down, and a driving mechanism that drives the working device to move up and down is provided.
Detection values of the angle sensor for detecting a steering angle of the front wheels from the turning of the body is started reaches from the steering limit side of the setting angle set from the steering limit of the predetermined angle straight side, and, of the aircraft A working device for a work vehicle configured to automatically lower the working device in a raised state to the ground when a measured value of a timer that measures the passage of time since the start of turning reaches a set time. Elevating structure.   The work device lifting structure for a work vehicle according to claim 1, wherein the set distance is changeable.   The work device lifting structure for a work vehicle according to claim 2 or 3, wherein the set time is changeable.   The working device lifting structure for a work vehicle according to any one of claims 1 to 5, wherein the set angle is configured to be changeable to a steering limit side and a straight traveling position side.   The start of turning of the airframe is configured to be detected by an operation to a detected value of the angle sensor or a lifted position of a lifting lever for the working device. The working device lifting structure of the described working vehicle. Configured to detect the start of turning of the airframe by operating the lift lever for the working device to the raised position;
The operation according to any one of claims 1 to 6, wherein a clutch that transmits power to the work device is operated to a disengagement side when the elevating lever is operated to a raised position. Car work device lifting structure. A right side clutch that can transmit and shut off power to the right rear wheel, and a left side clutch that can transmit and shut off power to the left rear wheel, with the steering operation of the front wheel. The side clutch is configured to be operated to the disengagement side,
The structure according to any one of claims 1 to 8, wherein when the detected value of the angle sensor reaches the set angle from the steering limit side, the side clutch on the turning center side is operated to the transmission side. The working device raising / lowering structure of the work vehicle as described in one.   If the lifting lever for the working device is operated to the raised position while the working device in the raised state is automatically lowered to the ground, the lowering of the working device is stopped and the working device is raised. The work device lifting structure for a work vehicle according to any one of claims 1 to 9, wherein the work device is lifted up and down.

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