JPH11217082A - Paddy field working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small turning circle by changing the prescribed braking force to the smaller side to prevent a paddy field from being damaged as much as possible when a side brake on the turning center side during the turn is operated to the braking side up to the prescribed braking force. SOLUTION: When a pitman arm 22 is started to steer from the first set angle on the right to further right side, a right side brake 24 on the right (the turning center side) is operated to the braking side by an electric cylinder 26. As the pitman arm 22 is largely steered from the first set angle on the right to further right side, the braking force of the side brake 24 on the right (the turning center side) becomes stronger, but the condition where the braking force of the side brake 24 on the right (the turning center side) becomes stronger, becomes slower than the condition where a sensitivity set dial is operated to the center between the insensitive side and the sensitive side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling system in a paddy field working vehicle such as a riding type rice transplanter or a riding type direct sowing machine.

[0002]

2. Description of the Related Art A riding type rice transplanter, which is an example of a paddy field working vehicle, has side brakes capable of independently braking the right and left rear wheels, and when the front wheels are steered to the right or left. It has been proposed that the side brake on the turning center side is automatically operated to the braking side. As a result, when one planting process is completed and the aircraft reaches the ridge, if the vehicle starts turning on the ridge to enter the next planting process (by steering the front wheel), the turning center side Is automatically operated to the braking side, and a small turning operation can be performed near the ridge by a braking operation on the rear wheel on the turning center side.

[0003]

SUMMARY OF THE INVENTION In a paddy field working vehicle,
As mentioned above, when turning by operating the side brake on the turning center side to the braking side, a small turning can be done,
On the contrary, the rice field may be damaged. If the rice field at the edge of the ridge is roughened in this way, for example, when performing seedling planting at the edge of a ridge in a riding type rice transplanter, it is necessary to level the rice field at the edge of the ridge sufficiently beforehand. Planting may be difficult. The present invention provides a paddy working vehicle configured such that a side brake on a turning center side is automatically operated to a braking side during a turn, so that a small turn can be performed while minimizing a rough surface of a rice field. The purpose is.

[0004]

Means for Solving the Problems [I] In a paddy field working vehicle, of the front wheels and the rear wheels, the rear wheel on the turning center side is closest to the turning center of the body, and the turning radius of the rear wheel on the turning center side. It is said that when turning with the side brake on the turning center side toward the braking side, the rear wheel on the turning center side does not move and turns sideways on the spot when turning In this state, the rear wheel on the turning center side is most likely to roughen the rice field.

According to the first and second aspects of the present invention, when the side brake on the turning center side is operated toward the braking side to make a small turn, there is a possibility that the rear wheel on the turning center side may roughen the rice field. When the side brake on the turning center side is operated toward the braking side to the predetermined braking force during turning, the predetermined braking force may be changed to the weak side. As a result, at the time of turning, the side brake on the turning center side is operated to the braking side, but it is possible to obtain a state in which the rear wheel on the turning center side is rotating to some extent. It is possible to avoid a situation where the player turns sideways on the spot without moving. Conversely, if there is no danger of roughening the rice field with the rear wheel on the turning center side, or if there is no problem in the subsequent work even if the rice field is roughened with the rear wheel on the turning center side, the aforementioned predetermined control is performed. The power should be changed to the strong side. Thus, a sufficiently small turning can be performed by a strong braking action on the rear wheel on the turning center side.

[II] According to the feature of claim 2, in addition to the "action" described in the above item [I], the following "action" is provided.
It has. In a four-wheel drive paddy working vehicle, a first state in which the front wheel and the rear wheel are driven at substantially the same speed, and a speed difference between the front wheel and the rear wheel such that the front wheel is driven at a higher speed than the rear wheel. It has been proposed to provide a speed difference transmission that can be freely switched to a given second state so that the speed difference transmission can be switched from the first state to the second state during turning.

According to the second aspect of the present invention, in a small turning operation in which the side brake on the turning center side is operated to the braking side, the front wheels and the rear wheels are actively driven by the second state of the speed difference transmission. A difference (the front wheel is high speed and the rear wheel is low speed) is given, and the speed difference between the front wheel and the rear wheel due to the difference between the inner and outer wheels is absorbed, and the small turning is smoothly performed.

[III] According to the feature of the third aspect, similar to the case of the first or second aspect, the "action" described in the above-mentioned [I] and [II] is provided. Has "action". When the mud on the rice field is soft, it means that a lot of water is present on the rice field, so that even if the rice field is roughened in a soft mud condition, the rough surface may disappear naturally. On the other hand, when the mud on the rice field is hard, it means that there is not much water on the rice field. Therefore, if the rice field is roughened while the mud is hard, the rough rice field may not disappear.

According to the third aspect of the present invention, as the adjusting means, which is adjusted in accordance with the hardness of the mud on the rice field, is adjusted to the harder side, the side brake on the turning center side during turning turns to a predetermined braking force. When operated on the braking side, the predetermined braking force is changed to the weak side. Therefore, in a case where the mud on the rice field is hard, it is possible to avoid a state in which the rear wheel on the turning center side does not move and turns sideways on the spot.

[IV] According to the feature of claim 4, similar to the case of claim 1 or 2, the "action" described in the above-mentioned [I] and [II] is provided. Has "action". In a riding type rice transplanter that is an example of a paddy field vehicle, auxiliary wheels are configured to be mounted concentrically on the outside and inside of the rear wheel, which is the main propulsion wheel, so that in the case of a paddy field that easily slips, There is a configuration in which the propulsive force of the wheels is transmitted not only through the rear wheels but also through the auxiliary wheels. When the auxiliary wheel is attached to the rear wheel in this manner, the width of the rear wheel (auxiliary wheel) is apparently widened, and therefore, in this state, when the side brake on the turning center side is operated to the braking side during turning. , The rear wheel (auxiliary wheel) on the turning center
May damage the rice field.

According to a fourth aspect of the present invention, when the auxiliary wheel is attached to the rear wheel, a predetermined braking force is applied when the side brake on the turning center side is operated toward the braking side to a predetermined braking force during turning. Is changed to the weak side. As a result, when turning, the side brake on the turning center side is operated to the braking side, but the rear wheel (auxiliary wheel) on the turning center side can be rotated to some extent. A situation in which the rear wheel (auxiliary wheel) turns sideways on the spot without moving can be avoided.

[V] According to the feature of claim 5, claim 1
As in any one of the above [I] to [4],
It has the “action” described in [IV], and additionally has the following “action”. According to the feature of claim 5, when the side brake on the turning center side is operated toward the braking side up to a predetermined braking force during turning, the right or left steering operation of the front wheel causes the turning brake on the turning center side to be suddenly operated. As if being operated on the braking side up to a predetermined braking force, or gradually being operated on the braking side up to a predetermined braking force,
The characteristic that the side brake on the turning center side is operated on the braking side can be changed. Thereby, according to the condition of the paddy field (hardness of mud on the surface, depth of cultivator, etc.) and work form,
The characteristic that the side brake on the turning center side is operated to the braking side up to a predetermined braking force can be set and changed to an appropriate one.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a seedling planting device 3 is provided with a link mechanism 4 and a rear portion of a body supported by a pair of left and right front wheels 1 and a pair of left and right rear wheels 2 which can be steered. A riding type rice transplanter, which is an example of a four-wheel drive type paddy working vehicle, is connected by a hydraulic cylinder 5 so as to be able to move up and down freely.

Next, the traveling transmission system of the riding type rice transplanter will be described. As shown in FIG. 2, the power of an engine 6 disposed at the front of the body is transmitted to a transmission case 9 at the rear of the body via a main clutch 7 and a transmission shaft 8. The power transmitted to the transmission case 9 is transmitted to a hydrostatic type continuously variable transmission 10 capable of continuously changing the speed in a forward and reverse direction, a subtransmission 11 capable of performing a high and low speed change, and a rear wheel differential device. 12 to the right and left rear wheels 2. The power branched immediately before the rear wheel differential device 12 is transmitted to the right and left front wheels 1 via a hydraulically operated front wheel transmission device 13, a transmission shaft 14, and a front wheel differential device 15.

Next, the front wheel transmission 13 will be described. As shown in FIG. 2, a standard gear 17 and a speed-increasing gear 18 are fitted on a support shaft 16 connected to the transmission shaft 14 so as to be rotatable relative to each other, and the power branched immediately before the rear wheel differential device 12 is transmitted. The power is transmitted to the standard gear 17 and the speed increasing gear 18 via the shaft 21. Between the support shaft 16 and the standard gear 17, a friction multi-plate type hydraulically operated first clutch 19 is provided. Between the support shaft 16 and the speed increasing gear 18, a friction multi-plate type hydraulically operated type first clutch 19 is provided. Two clutches 20 are provided. As a result, when the first clutch 19 is operated to the transmission side, power is transmitted to the front wheel differential device 15 in the first state in which the front wheel 1 and the rear wheel 2 are driven at substantially the same speed.
When the second clutch 20 is operated to the transmission side, the front wheel differential device 1 is driven in the second state in which the front wheels 1 are driven at a higher speed than the rear wheels 2.
Power is transmitted to 5.

As shown in FIG. 3, the hydraulic oil is supplied to the electromagnetic switching valve 2
7 to the front wheel transmission 13. In the electromagnetic switching valve 27, the first clutch 19
A first position 27A where hydraulic oil is supplied to the first clutch 19 to operate the transmission side, and a second position 2A where hydraulic oil is supplied to the second clutch 20 to operate the second clutch 20 to the transmission side.
7B, and the electromagnetic switching valve 27 is biased to a first position 27A by a spring.

As shown in FIGS. 2 and 3, a pair of left and right side brakes 24 capable of independently braking the right and left rear wheels 2 and a pair of right and left left and right side brakes 24 which can be independently operated on the braking side. Is provided. An electric cylinder 26 capable of operating the right and left side brakes 24 on the braking side and the braking release side is provided.

Next, the raising / lowering control of the seedling planting apparatus 3 during planting traveling will be described. As shown in FIGS. 3 and 1, the rear portion of the sensor float 29 provided at the lower left and right center of the seedling planting device 3 is supported so as to be able to swing up and down around the horizontal axis P1. The detection arm 30a of the provided potentiometer 30 and the front part of the sensor float 29 are connected by a link rod 31. Spring 3
2, the front part of the sensor float 29 is urged downward via the detection arm 30a and the link rod 31. The detection value of the potentiometer 30 of the sensor float 29 is input to the control device 33, and the detection value of the potentiometer 30 indicates the vertical distance between the front part of the sensor float 29 and the seedling planting device 3 (potentiometer 30). .

Therefore, when the seedling planting device 3 moves up and down while the sensor float 29 follows the ground surface as the aircraft advances, the sensor float 29 moves around the horizontal axis P1.
Is moved up and down, the control device 33 operates the control valve 28 so that the detection value of the potentiometer 30 becomes the set value C (so that the detection arm 30a of the potentiometer 30 becomes the posture of the set value C). Then, the hydraulic cylinder 5 is operated to expand and contract, and the seedling planting apparatus 3 is automatically moved up and down. Thereby, the seedling planting apparatus 3 is maintained at the set height from the rice field, and the planting depth of the seedlings by the seedling planting apparatus 3 is maintained at the set value.

Next, a description will be given of a change in the control sensitivity in the above-described elevating operation. As shown in FIG. 3, a sensitivity setting dial 34 that can be operated artificially is provided on the control unit of the aircraft, and the setting value of the sensitivity setting dial 34 is
3 has been entered. In this case, if the driver determines that the mud on the rice field is hard, the sensitivity setting dial 34 may be operated to the insensitive side, and if the driver determines that the mud on the rice field is soft, the sensitivity setting dial 34 is moved to the sensitive side. You just need to do it.

Thus, when the sensitivity setting dial 34 is operated to the insensitive side, the set value C shown in FIG. 3 is automatically changed to the upward insensitive side, and the detection value of the potentiometer 30 is changed to the upward set value. C (so that the detection arm 30a of the potentiometer 30 is in the posture of the upward set value C), the seedling planting apparatus 3 is automatically moved up and down. At this upward set value C, the posture of the sensor float 29 is on the front-up side, so that the contact area of the sensor float 29 with the rice paddle surface is reduced, the spring 32 is compressed, and the urging force of the spring 32 is increased. Float 29
The contact sensitivity (control sensitivity of the lifting operation) to the rice field is changed to the insensitive side.

Conversely, when the sensitivity setting dial 34 is operated to the sensitive side, the set value C shown in FIG. 3 is automatically changed to the downward sensitive side, and the detection value of the potentiometer 30 is changed to the downward set value C. (So that the detection arm 30a of the potentiometer 30 has the posture of the downward set value C), the seedling planting apparatus 3 is automatically moved up and down. In this downward set value C, the posture of the sensor float 29 is on the front downward side, so that the contact area of the sensor float 29 to the rice field surface is increased, the spring 32 is extended, and the urging force of the spring 32 is weakened. The sensitivity of the float 29 to follow the ground surface (the control sensitivity of the lifting operation) is changed to the sensitive side.

Next, a description will be given of a state of turning on a ridge. As shown in FIGS. 3 and 2, a pitman arm 22 for steering the front wheel 1 is provided, and a potentiometer 23 for detecting right and left steering angles of the pitman arm 22 from the straight traveling position A is provided. , The detection value of the potentiometer 23 is input to the control device 33. As a result, when one planting process is completed and the aircraft reaches the ridge, the driver greatly raises the seedling planting device 3 to operate the planting plant shown in FIG.
The pitman arm 22 is controlled by the steering handle 35 shown in FIG.
The steering operation of the (front wheel 1) is started rightward or leftward from the straight traveling position A to start turning. In this state, the front wheel transmission 13
Is still in the first state, and the right and left side brakes 24
Is not operated on the braking side.

Between the straight traveling position A of the pitman arm 22 and the right and left steering limits B, the right and left first set angles A are set.
1 is set, and the pitman arm 22 is steered, for example, rightward from the straight traveling position A, and the right first set angle A1 is set.
4, the electromagnetic switching valve 27 is operated from the first position 27A to the second position 27B by the control device 33, and the front wheel transmission 13 is switched from the first state to the second state as shown in FIG. .

Next, when the pitman arm 22 starts to be steered further rightward from the first set angle A1 on the right, FIG.
As shown by the solid line D1, the right (turn center side) side brake 24 starts to be operated to the braking side by the electric cylinder 26. In this case, the more the pitman arm 22 is steered to the right from the right first set angle A1, the stronger the braking force of the right (turn center side) side brake 24 becomes. When the right second set angle A2 is reached, the right (turn center side) side brake 2
Even if the pitman arm 22 is steered beyond the right second set angle A2 when the braking force of No. 4 reaches the predetermined first braking force F1, the braking force of the right (turning center side) side brake 24 is maintained. The predetermined first braking force F1 is maintained. Solid line D in FIG.
The state shown in FIG. 1 is a state where the sensitivity setting dial 34 shown in FIG. 3 is operated at the center between the insensitive side and the sensitive side.

Next, it is assumed that the driver has determined that the mud on the rice field is hard and has operated the sensitivity setting dial 34 to the insensitive side.
In this state, when the pitman arm 22 (front wheel 1) starts to be steered to the right or left from the straight traveling position A by the steering handle 35 to start turning, the front wheel transmission 13 is still in the first state, and When the left side brake 24 is not operated on the braking side and the pitman arm 22 is steered from the straight traveling position A, for example, to the right and reaches the first set angle A1 on the right, as shown in FIG. 33, the electromagnetic switching valve 27 is moved from the first position 27A to the second position 27B.
, The front wheel transmission 13 is switched from the first state to the second state.

Next, when the pitman arm 22 starts to be steered further rightward from the right first set angle A1, FIG.
As shown by the one-dot chain line D2, the right (turn center side) side brake 24 starts to be operated to the braking side by the electric cylinder 26. In this case, the more the pitman arm 22 is steered from the right first set angle A1 to the right, the stronger the braking force of the right (turn center side) side brake 24 becomes. As shown in the figure, the right (turn center side) side brake 24 is more shifted than the state where the sensitivity setting dial 34 is operated at the center between the insensitive side and the sensitive side.
The state in which the braking force is increased becomes gentle. When the pitman arm 22 reaches the right third set angle A3 on the steering limit B side of the right second set angle A2, the braking force of the right (turn center side) side brake 24 becomes a predetermined second braking force. F2 (smaller than the predetermined first braking force F1), and even if the pitman arm 22 is steered beyond the right third set angle A3, the braking force of the right (turn center side) side brake 24 is operated. Is maintained at a predetermined second braking force F2.

Next, it is assumed that the driver determines that the mud on the rice field is soft and operates the sensitivity setting dial 34 to the sensitive side. In this state, when the pitman arm 22 (front wheel 1) is steered to the right or left from the straight traveling position A by the steering handle 35 to start turning, the front wheel transmission 1
3 is still in the first state and the right and left side brakes 2
4 is not operated on the braking side, and the pitman arm 22 is not operated.
Is steered from the straight traveling position A to the right, for example, and reaches the first set angle A1 on the right, as shown in FIG.
From the first position 27A to the second position 2
7B, the front wheel transmission 13 is switched from the standard state to the speed increasing state.

Next, when the pitman arm 22 starts to be steered further rightward from the right first set angle A1, FIG.
As shown by the one-dot chain line D3, the right (turn center side) side brake 24 starts to be operated to the braking side by the electric cylinder 26. In this case, the more the pitman arm 22 is steered from the right first set angle A1 to the right, the stronger the braking force of the right (turn center side) side brake 24 becomes. As shown in the figure, the right (turn center side) side brake 24 is more shifted than the state where the sensitivity setting dial 34 is operated at the center between the insensitive side and the sensitive side.
The state in which the braking force is increased becomes sudden. When the pitman arm 22 reaches the fourth set angle A4 on the right side of the straight traveling position A from the second set angle A2 on the right, the right (turning center side)
The braking force of the side brake 24 is equal to a predetermined third braking force F3.
(Greater than the predetermined first braking force F1), and even if the pitman arm 22 is steered beyond the right fourth set angle A4, the braking force of the right (turn center side) side brake 24 is maintained. The predetermined third braking force F3 is maintained.

The solid line D1, the dash-dot lines D2 and D3 shown in FIG.
Is set continuously according to the position of the sensitivity setting dial 34. Thus, the more the sensitivity setting dial 34 is operated from the center between the insensitive side and the sensitive side to the sensitive side, the more the solid line D1 moves toward the one-dot chain line D2 and exceeds the one-dot chain line D2. 34, the more the center is moved between the insensitive side and the sensitive side to the insensitive side,
The solid line D1 moves to the dashed line D3 side, and the dashed line D3
Going beyond.

[First Embodiment of the Invention] Instead of the configuration shown in FIGS. 1 to 4, it may be configured as shown in FIGS. A front wheel transmission 13 provided in the transmission case 9 as shown in FIG. 2 is disposed at a rear portion of the front axle case 36 as shown in FIGS. 5 and 6, and branches immediately before the rear wheel differential device 12 shown in FIG. The transmitted power is transmitted to the input shaft 39 of the front wheel transmission 13 via the transmission shafts 21 and 14.

As shown in FIG. 6, a front wheel transmission 13 is fixed to the front of the body, and a boss 13A at the front end of the front wheel transmission 13 and a support member 40 fixed to the front of the body are provided. A front axle case 36 is supported so as to freely roll around a front-rear axis X, and front wheels 1 are supported at both ends of the front axle case 36 so as to be steerable left and right. A first standard gear 41 and a first standard gear 41 are provided on the input shaft 39 of the front wheel transmission 13.
The second speed increasing gear 42 is fixed, and the second standard gear 46 and the second speed increasing gear 4 are rotatably supported on the output shaft 51.
7 is in mesh with the first standard gear 41 and the first speed increasing gear 42.

The shift member 50 has a spline structure,
The output shaft 51 is slidably and integrally rotatably fitted to the outside of the output shaft 51, and a friction multi-plate type speed increasing clutch 52 is provided between the second speed increasing gear 47 and the output shaft 51. The front wheel differential device 15 is supported by the front axle case 36, and the gear 51A of the output shaft 51 of the front wheel transmission 13 is engaged with the input gear 15A of the front wheel differential device 15.

As a result, when the shift member 50 is slid rightward on the drawing sheet as shown in FIG. 6 to engage with the second standard gear 46, the power is supplied to the first and second standard gears 41 and 4.
6. The power is transmitted to the left and right front wheels 1 via the output shaft 51 and the front wheel differential device 15 in the first state in which the front wheels 1 and the rear wheels 2 are driven at substantially the same speed. When the shift member 50 is slid leftward on the paper from the state shown in FIG. 6 and the speed-increasing clutch 52 is pressed to operate the speed-increasing clutch 52 to the transmission side, power is supplied to the first and second speed-increasing gears 42 and 47. The front wheel 1 is transmitted to the left and right front wheels 1 via the output shaft 51 and the front wheel differential device 15 in a second state in which the front wheels 1 are driven at a higher speed than the rear wheels 2.

Next, the operation structure of the front wheel transmission 13 will be described. As shown in FIGS. 5 and 6, the front wheel transmission 1
3 is provided with a shift fork 53 that slides the shift member 50, and an operation shaft 55 that is slidable on the shift fork 53 is provided, and the operation shaft 5 is operated by a spring (not shown).
5 is biased toward the first state. Pitman arm 2
2, the cam plate 57 is fixed to the longitudinal axis P1 of the body fixing portion.
Pin 61 of cam arm 61 supported so as to be swingable around
A is engaged with the cam hole of the cam plate 57. A link rod 37 is connected between the operation shaft 55 of the front wheel transmission 13 and the cam arm 61.

With the above structure, the pitman arm 22
When the (front wheel 1) is steered from the straight traveling position A by more than the right or left first set angle A1, the cam action between the cam hole and the pin 61A causes the cam arm 61 to move counterclockwise in FIG. By the swing operation, the link rod 37 is moved to the cam arm 61.
It is operated to the side. As a result, the shift member 50 is slid by the operation shaft 55 and the shift fork 53 to push the speed increasing clutch 52 to operate on the transmission side, so that the front wheel 1 is driven at a higher speed than the rear wheel 2. Become.

In the above state, when the pitman arm 22 (front wheel 1) is steered from the straight traveling position A to the right or left set angle A1 or more, the front wheel transmission 13 switches from the first state to the second state. It is in a state of being operated. As shown in FIG. 5, the operation shaft 55 is slid to operate the shift fork 53.
An operation arm 38 is provided to perform a separation operation from the control arm. A first operation lever 44 provided on a control section of the fuselage and the operation arm 38 are linked to each other by a linkage mechanism 63.
Accordingly, when the operation shaft 55 is separated from the shift fork 53 by the first operation lever 44, even if the pitman arm 22 (the front wheel 1) is steered from the straight traveling position A to the right or left set angle A1 or more, the operation is performed. Only when the shaft 55 idles, the shift fork 53 is not slid, and the front wheel transmission 13 remains in the first state.

As shown in FIG. 5, a right and left brake operation mechanism 48 is provided for each of a pair of left and right side brakes 24 capable of independently braking the right and left rear wheels 2, respectively. The brake operation mechanism 48 is constructed as follows. As shown in FIGS. 7 and 8, the side brake pedal 25 is fixed to a boss member 49 rotatably supported around the horizontal axis P2. The first arm 49A fixed to the boss member 49 and the operation arm 24A of the side brake 24 are connected by a wire 54 (inner 54A) and a spring 65. Side brake pedal 2
Reference numeral 5 is arranged at the right front portion of the fuselage. By depressing the side brake pedal 25, the side brake 24 can be operated to the braking side.

The first arm 49A of the boss member 49 has a long hole 4
9C and a separately provided linkage arm 56
Is inserted into the elongated hole 49C of the first arm 49A. A vertically long concave portion 56B is formed in the link arm 56, and the pin 49D of the second arm 49B fixed to the boss member 49 is inserted into the concave portion 56B of the link arm 56.

As shown in FIGS. 5 and 7, around a longitudinal axis of a support frame (not shown) disposed at the front of the body,
A pair of left and right operation arms 58 are swingably supported, and rollers (not shown) of the right and left operation arms 58 are in contact with the cam plate 57 at the straight traveling position A of the pitman arm 22 (front wheel 1). Hit. The right and left operation arms 58 and the link arm 56 (pin 56 </ b> A) of the right and left brake operation mechanisms 48 are connected by a flexible spring 59 and a wire 60, and have a smaller urging force than the spring 59. The return spring 62 is connected to the pin 56A of the link arm 56.

With the above structure, for example, when the pitman arm 22 (front wheel 1) starts to be steered rightward from the straight traveling position A, the cam plate 57 fixed to the pitman arm 22 is started.
Starts swinging the right operation arm 58, and
Begins to be pulled. As a result, when the wire 60 is pulled to the left in FIG. 7 by the right brake operation mechanism 48, the boss member 49 is engaged by the engagement of the concave portion 56B of the link arm 56 and the pin 49D of the second arm 49B. 7, the right side brake 24 is operated to the braking side by the first arm 49A of the boss member 49 and the wire 54 (inner 54A).

As shown in FIG. 7, each of the right and left side brakes 24 is provided with a setting lever 66 which can swing freely around the horizontal axis P3, and a left and right auxiliary step located above the rear wheel 2. From 68 (see FIG. 1), the setting lever 66 protrudes upward. An engagement type lever guide 67 capable of holding the setting lever 66 at three positions of a strong position, a middle position, and a weak position is provided in the auxiliary step 68, and the end of the outer 54B of the wire 54 is connected to the setting lever 66. It is supported by.

The state shown in FIG. 7 is a state in which the setting lever 66 is operated to the strong position.
4B is moved leftward in FIG. 7 to slightly extend the spring 65, and a certain initial tension is applied to the spring 65. This initial tension is caused by the state in which the pitman arm 22 (front wheel 1) is not steered from the straight traveling position A (the state in which the wire 54 (inner 54A) is not pulled) and the step on the side brake pedal 25. In the absence state, the limit value is set to the limit at which the side brake 24 is not operated on the braking side. As a result, as described above, the pitman arm 22 (front wheel 1) is steered right or left from the straight traveling position A, the wire 54 (inner 54A) is pulled, and the side brake 24 on the turning center side is turned on the braking side. Is operated, the braking force of the side brake 24 on the turning center side becomes strong.

Next, when the setting lever 66 is operated to the middle position, the amount of extension of the spring 65 becomes smaller than in the above-described strong position, and the initial tension applied to the spring 65 is smaller than in the strong position. It will be. As a result, the pitman arm 22 (front wheel 1) is steered right or left from the straight traveling position A, the wire 54 (inner 54A) is pulled, and the side brake 24 on the turning center side is operated on the braking side. At this time, the braking force of the side brake 24 on the turning center side is slightly weaker than the braking force at the strong position.

Next, when the setting lever 66 is operated to the weak position, the amount of extension of the spring 65 becomes smaller than in the case of the above-described middle position, and the initial tension applied to the spring 65 is smaller than in the case of the middle position. It will be. As a result, the pitman arm 22 (front wheel 1) is steered right or left from the straight traveling position A, the wire 54 (inner 54A) is pulled, and the side brake 24 on the turning center side is operated on the braking side. At this time, the braking force of the side brake 24 on the turning center side is slightly weaker than the braking force at the middle position.

As shown in FIG. 9, there is a riding type rice transplanter in which an auxiliary wheel 69 is mounted concentrically on the outside or inside of the rear wheel 2. Thus, when the auxiliary wheel 69 is not mounted on the rear wheel 2, the setting lever 66 shown in FIG. 7 may be operated to the strong position. When the auxiliary wheel 69 is mounted on the inside or outside of the rear wheel 2, The setting lever 66 may be operated to the middle position. When attaching the auxiliary wheels 69 to both the inside and the outside of the rear wheel 2, the setting lever 66 may be operated to the weak position.

As shown in FIGS. 5, 7, and 8, the second operation lever 43 is disposed on the control section of the aircraft, and the link arm 56 of the right and left brake operation mechanisms 48 and the second operation lever 43 are connected to each other. , Are connected by a pair of wires 64. Thus, when the wire 64 is pulled by the second operation lever 43, the linking arms 56 of the right and left brake operation mechanisms 48 in FIG. 7 are pivoted in the counterclockwise direction on the drawing sheet as indicated by the two-dot chain line. The concave portion 56 of the link arm 56
B moves away from the pin 49D of the second arm 49B to the right in the drawing.

Therefore, in this state, the pitman arm 2
2 (front wheel 1) is steered to the right or left from the straight traveling position A, and the wire 60 is pulled to the left in FIG.
By simply moving the pin 56A of the link arm 56 to the left of the drawing along the elongated hole 49C of the first arm 49A, the boss member 4
9 is not rotated counterclockwise in the drawing, and the side brake 24 on the turning center side is not operated on the braking side.

Second Embodiment of the Invention In the "Embodiment of the invention" shown in FIGS. 1 to 4, an auxiliary wheel 69 is mounted concentrically on the outside or inside of the rear wheel 2. In this case, as shown in FIG. 9, a presence / absence sensor 70 for detecting the presence or absence of the auxiliary wheel 69 is provided, and when the auxiliary wheel 69 is not attached to the rear wheel 2, the dashed line D3 in FIG. 4 is automatically set. When the auxiliary wheel 69 is mounted inside or outside the rear wheel 2, the solid line D1 in FIG. 4 is automatically set, and the auxiliary wheel 69 is mounted both inside and outside the rear wheel 2. In such a case, the configuration may be such that the dashed line D2 in FIG. 4 is automatically set. In the embodiment of the invention shown in FIGS.
Instead, a mud hardness sensor (not shown) for automatically detecting the mud hardness of the rice field is provided, and based on the detection value of the mud hardness sensor, a solid line D1 and a dashed-dotted line D2 shown in FIG. , D
3 may be automatically set.

In the above [Embodiment of the invention], [First alternative embodiment of the invention] and [Second alternative embodiment of the invention], front wheel 1 and rear wheel 2 are replaced with front wheel transmission 13. Are driven at substantially the same speed, and the rear wheel 2 is the front wheel 1
A rear wheel transmission (not shown) may be provided which can be switched to the second state driven at a lower speed. In the dashed lines D2 and D3 shown in FIG. 4, when the steering angle of the pitman arm 22 reaches the second set angle A2 from the first set angle A1 as in the case of the solid line D1, predetermined second and third braking forces are set. You may comprise so that it may reach F2 and F3. In the configuration shown in FIG. 4, the first set angle A1 at which the side brake 24 on the turning center side starts to be operated on the braking side is a different set angle (for example, a set angle closer to the straight-moving position A than the first set angle A1). Alternatively, the front wheel transmission 13 may be configured to be switched to the second state.

[0051]

According to the first and second aspects of the present invention, in a paddy field working vehicle configured such that the side brake on the turning center side is automatically operated to the braking side during turning, the side brake on the turning center side is provided. By configuring the predetermined braking force to be operated on the braking side to be strong or weak according to the state of the paddy field, etc., a small turning operation can be performed by a strong braking action on the rear wheel on the turning center side, or the turning center can be changed. The weak braking action on the rear wheel on the side allows the vehicle to make turns while suppressing the rough surface of the rice field, thereby improving the traveling performance of the paddy field work vehicle.

According to the second aspect of the present invention, in a four-wheel drive type paddy working vehicle, the front wheel and the rear wheel are controlled by the second state of the speed difference transmission during a small turning operation by operating the side brake on the turning center side to the braking side. Positively gives speed difference to the wheels (front wheel is high speed and rear wheel is low speed), absorbs the speed difference between front and rear wheels due to the difference between inner and outer wheels, and enables smooth small turning Was able to further improve the running performance.

According to the feature of claim 3, claim 1 or 2
"Effects of the Invention" of Claim 1 or 2 as in the case of
In addition to this “effect of the invention”, the following “effect of the invention” is provided. According to the feature of claim 3, when the side brake on the turning center side is operated to the braking side up to a predetermined braking force at the time of turning, in conjunction with the adjusting means adjusted according to the hardness of mud on the rice field, Since the predetermined braking force is automatically changed, the operability of the paddy field working vehicle can be improved.

According to the features of claim 4, claim 1 or 2
"Effects of the Invention" of Claim 1 or 2 as in the case of
In addition to this “effect of the invention”, the following “effect of the invention” is provided. According to the feature of claim 4, when the side brake on the turning center side is operated to the braking side up to the predetermined braking force at the time of turning, the predetermined braking force is automatically set according to the presence or absence of the auxiliary wheel on the rear wheel. Since the change operation was performed, the operability of the paddy field working vehicle could be improved.

According to the feature of claim 5, as in the case of any one of claims 1 to 4, the "effect of the invention" of any one of claims 1 to 4 is provided. In addition to the “effects of the invention”, the following “effects of the invention” are provided. According to the feature of claim 5, when the side brake on the turning center side is operated to the braking side to a predetermined braking force during turning, the state of paddy fields (hardness of mud on the surface, depth of cultivator, etc.) and work are performed. Depending on the form, it can be set so that the side brake on the turning center side is operated to the braking side up to a predetermined braking force at a stretch, or is gradually operated to the braking side up to a predetermined braking force. As a result, the traveling performance of the paddy field working vehicle could be further improved.

[Brief description of the drawings]

FIG. 1 is an overall side view of a riding rice transplanter.

FIG. 2 is a schematic diagram showing a traveling power transmission system.

FIG. 3 is a diagram showing a linked state of a front wheel transmission, a side brake, and a pitman arm.

FIG. 4 is a diagram showing a relationship between a steering angle of a pitman arm from a straight traveling position and a braking force of a side brake on a turning center side.

FIG. 5 is a diagram showing a linked state between a front wheel transmission, a side brake, and a pitman arm according to the first alternative embodiment of the present invention;

FIG. 6 is a cross-sectional plan view of the vicinity of a front wheel transmission in a first alternative embodiment of the present invention;

FIG. 7 is a side view showing a linked state between a brake operating mechanism and a side brake according to the first alternative embodiment of the present invention;

FIG. 8 is a longitudinal rear view of a brake operation mechanism according to the first alternative embodiment of the present invention;

FIG. 9 is a rear view in a state where an auxiliary wheel is attached to a rear wheel in the second alternative embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel 13 Speed difference transmission 24 Side brake 26, 54, 58, 60 Operating means 34 Adjusting means 66 Braking force changing means 69 Auxiliary wheel 70 Detecting means D1, D2, D3 Characteristics F1, F2, F3 power

Continued on the front page (72) Inventor Takeshi Mukai 64 Ishizu-Kitamachi, Sakai City, Osaka Prefecture, in Kubota Sakai Works, Ltd. ) Inventor Masakazu Furuichi 64 Ishizukita-cho, Sakai-shi, Osaka, Japan, inside Kubota Sakai Works, Ltd. 64, Ishizu-Kitacho, Sakai-shi, Osaka, Japan Kubota Sakai Factory (72) Inventor Susumu Yamamoto 64, Ishizu-Kitacho, Sakai-shi, Osaka Prefecture, Kubota Sakai Factory

Claims (5)

[Claims] 1. A side brake capable of independently braking the right and left rear wheels, and the side brake on the turning center side when the front wheel is steered to the right or left to a predetermined braking force to the braking side. A paddy field working vehicle comprising: an operating means for operating; and a braking force changing means capable of freely changing the predetermined braking force. 2. A switch between a first state in which the front wheels and the rear wheels are driven at substantially the same speed and a second state in which a front wheel and a rear wheel have a speed difference so that the front wheels are driven at a higher speed than the rear wheels. An operable speed difference transmission, a side brake capable of independently braking the right and left rear wheels, and a speed change transmission from the first state to the second state when the front wheel is steered right or left. Operating means for switching to a state, and operating the side brake on the turning center side to the braking side up to a predetermined braking force, and braking force changing means capable of changing the predetermined braking force strongly and weakly. Paddy working vehicle. 3. The predetermined braking force when the side brake on the turning center side is operated to the braking side by the operating means as the adjusting means adjusted in accordance with the hardness of the mud on the rice field is adjusted to the harder side. 3. The paddy field working vehicle according to claim 1, wherein braking force changing means is configured to change the braking force to a weak side. 4. An auxiliary wheel is concentrically mounted on a rear wheel, and detection means for detecting whether or not the auxiliary wheel is mounted on the rear wheel is provided. The auxiliary wheel is mounted on the rear wheel. The braking force changing means is configured to change a predetermined braking force when the side brake on the turning center side is operated to the braking side by the operating means to a weak side when the operation means is attached. 2. The paddy field working vehicle according to 2. 5. When the front wheel is steered right or left and the side brake on the turning center side is operated to the braking side up to a predetermined braking force by the operating means, the side brake on the turning center side is turned on the braking side. The paddy field working vehicle according to any one of claims 1 to 4, further comprising a characteristic changing unit that changes a characteristic to be operated.