JPH0752668A - Four-wheel-drive paddy working vehicle - Google Patents

Abstract

PURPOSE:To allow a four-wheel-drive paddy working vehicle to smoothly move in a small circle when making a turn at a ridge between paddies, without damaging the surface of the paddies. CONSTITUTION:A four-wheel-drive paddy working vehicle is provided with a rear-wheel transmission 10 which can be freely switched between a normal state in which front 1 and rear 2 running wheels are driven at approximately equal speeds and a rear-wheel decelerating state in which the rear wheels 2 are driven at lower speed than the front wheels 1, and when the body of the vehicle comes to a ridge between paddies and a working clutch 12 is switched off, the rear-wheel transmission 10 is automatically switched from the normal state to the rear-wheel decelerating state in accordance with the switching operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a traveling system in a four-wheel drive type paddy field working vehicle such as a riding type rice transplanter and a riding type direct seeder.

[0002]

2. Description of the Related Art A passenger type rice transplanter, which is an example of a four-wheel drive type paddy field vehicle, is disclosed in, for example, JP-A-63-230009.
As disclosed in Japanese Patent Publication, it is possible to freely switch between a standard state in which front and rear wheels for driving are driven at substantially the same speed, and a rear wheel deceleration state in which the rear wheels are driven at a lower speed than the front wheels. Some rear wheel transmissions (11 in FIG. 1 of the above publication) are provided.

As a result, when one planting stroke is completed and the aircraft reaches the edge of the road, steering operation of the front wheels is started, and one side brake pedal is depressed to operate the rear wheels on the turning center side. When the vehicle is braked to start turning at the edge, the rear wheel transmission is switched from the standard state to the rear wheel decelerating state in conjunction with the stepping operation of the side brake pedal. In this way, when the vehicle turns at the edge of the ridge, the rear wheels are decelerated from the front wheels to give a speed difference between the front wheels and the rear wheels, so that the aircraft smoothly makes a small turn without roughening the rice field.

[0004]

In the riding type rice transplanter as described above, when turning at the edge, after the front wheel is steered largely to the right or left and the aircraft starts to turn, the turning center side It is in a state where the side brake pedal is operated.

Therefore, even if the rear wheel transmission is switched to the rear wheel deceleration state in conjunction with the stepping operation of one of the side brake pedals, it is slightly slower, and the front wheels and the rear wheels are still driven at the same speed immediately after the start of turning. In some cases, the front surface and the rear wheels may damage the rice field immediately after the start of turning. It is an object of the present invention to further reduce the state in which a paddy field is roughened when turning at a ridge in a four-wheel drive type paddy field vehicle equipped with a rear wheel reduction gear.

[0006]

A feature of the present invention is that the four-wheel drive type paddy work vehicle as described above is configured as follows. That is, the rear wheel transmission is provided which is switchable between a standard state in which the front wheels and the rear wheels for traveling are driven at substantially the same speed and a rear wheel deceleration state in which the rear wheels are driven at a lower speed than the front wheels. , Equipped with a work clutch that performs transmission and transmission interruption operation to the ground work device supported by the aircraft, and in conjunction with the transmission interruption operation of this work clutch, the rear wheel transmission is switched from the standard state to the rear wheel deceleration state The switching means for switching is provided.

[0007]

[Operation] In the four-wheel drive type paddy work vehicle as described above, when one working stroke (planting stroke, etc.) is completed and the aircraft reaches the edge, first, the work clutch is disengaged to ground. After stopping the work device, the steering operation of the front wheels is started and the turning on the ridge is started. Therefore, when the rear wheel transmission is configured to be switched from the standard state to the rear wheel deceleration state in conjunction with the transmission disengagement operation of the work clutch as in the present invention, the rear wheel transmission can be changed slightly before and after the start of turning at the ridge. Since the wheels are driven at a lower speed than the front wheels, when making a turn at the ridge, the rear wheel is driven at a lower speed than the front wheel from the beginning of the turn, and the turn at the ridge is performed. Of.

[0008] In some cases, the vehicle may turn at the edge of the ridge only by steering the front wheels without depressing one of the side brake pedals. As a result, when the rear wheel transmission is configured to be switched to the rear wheel deceleration state by interlocking with the stepping operation of one of the side brake pedals as in the conventional structure, the rear wheel transmission is set to the rear wheel at the ridge. In some cases, the vehicle may make a turn without switching to the deceleration state. On the other hand, the work clutch transmission interruption operation as in the present invention is always the first operation to be performed when the machine body reaches the edge, so that the rear wheel is interlocked with the work clutch transmission interruption operation as in the present invention. If the transmission is configured to be switched to the rear wheel deceleration state, a situation in which the rear wheel transmission does not switch to the rear wheel deceleration state to make a turn at the edge of the wheel does not occur.

[0009]

As described above, the rear wheel transmission is switched to the rear wheel deceleration state in conjunction with the transmission disengagement operation of the work clutch, so that the rear wheel can be operated at a lower speed than the front wheel from the beginning. It becomes possible to make a turn at the edge of the road while being driven, and it is possible to further reduce the roughness of the rice field caused by turning while the front wheels and the rear wheels are being driven at the same speed. In this way, if it is possible to reduce the roughness of the paddy field at the edge of the ridge, the rice planting work near the edge of the ridge can be performed easily after this.

Further, if the rear wheel transmission is configured to be switched to the rear wheel deceleration state in conjunction with the transmission interruption operation of the work clutch, the rear wheel transmission is not switched to the rear wheel deceleration state. Since there is no situation in which the vehicle makes a turn at the edge of the ridge, it is possible to further reduce the roughness of the paddy field at the edge of the ridge.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, an engine 3 is provided at a front portion of a body supported by a pair of left and right front wheels 1 for traveling and a pair of left and right rear rear wheels 2, and a link mechanism 4 is provided at a rear portion of the body.
Further, the seedling planting device 5 (corresponding to the ground work device) is connected via the hydraulic cylinder 6 so as to be capable of lifting and lowering, thereby forming a riding type rice transplanter which is an example of a four-wheel drive type paddy work vehicle.

As shown in FIG. 2, the power from the engine 3 is transmitted to a gear transmission 8 having two forward gears and one reverse gear via a continuously variable transmission 7 of a split pulley type. And
Power from the gear transmission 8 is transmitted to the left and right front wheels 1 via the front wheel differential device 9, and is transmitted to the left and right rear wheels 2 via the rear wheel transmission device 10 and the rear wheel differential mechanism 11. It is branched in parallel into three transmission systems, that is, a transmission system and a transmission system that is transmitted to the seedling planting device 5 via the planting clutch 12 (corresponding to a work clutch).

Next, the rear wheel transmission 10 will be described. As shown in FIG. 2, the output shaft 1 from the gear transmission 8
3 and the input shaft 14 of the rear wheel differential mechanism 11 are arranged concentrically, and a shift gear 15 is externally fitted to the end of the output shaft 13 by a spline structure so as to be slidable. The shift gear 15 is urged by a spring 16 toward the side of engagement with the end of the input shaft 14, and the shift gear 15 is slid on the first transmission gear 17 that is fitted onto the output shaft 13 so as to be relatively rotatable. A first electric cylinder 18 (corresponding to a switching unit) is provided.

With the above structure, in a normal traveling state, the shift gear 15 slides to the right in the drawing by the urging force of the spring 16 and engages with the input shaft 14, and the front wheel 1 and the rear wheel 2 are driven at substantially the same speed. In the standard state, the power is transmitted from the output shaft 13 to the input shaft 14. On the contrary, the first electric cylinder 18
When the shift gear 15 is slid to the left side of the drawing by the above and engaged with the first transmission gear 17, the power of the output shaft 13 is transmitted from the front wheel 1 via the first transmission gear 17, the transmission shaft 19 and the second transmission gear 20. Also, power is transmitted from the output shaft 13 to the input shaft 14 in a deceleration state of the rear wheels in which the rear wheels 2 are driven at a low speed.

As shown in FIG. 2, the hydraulic cylinder 6 is operated by the operation of supplying / discharging the hydraulic oil from the control valve 21, the raising / lowering operation of the seedling planting device 5 is performed, and the seedling planting device 5 is planted. The auxiliary clutch 12 is operated by the second electric cylinder 22 for transmission and transmission interruption. As shown in FIGS. 2 and 1, the operation lever 24 is arranged on the right side of the steering handle 23 for steering the front wheel 1, and the operation position of the operation lever 24 is input to the control device 25.

As a result, when the operating lever 24 is operated to the planting position, the second electric cylinder 22 operates the planting clutch 12 to the transmission side based on the operation signal of the control device 25, and the seedling planting is performed as shown in FIG. The control valve 21 and the hydraulic cylinder 6 are arranged so that the device 5 is supported at a set height from the rice field G.
The seedling planting device 5 is automatically moved up and down.

When the operating lever 24 is operated to the raised position,
The second electric cylinder 22 based on the operation signal of the control device 25.
The planting clutch 12 is operated to the transmission shut-off side by the control valve, and the seedling planting device 5 is raised by the control valve 21 and the hydraulic cylinder 6. When the operation lever 24 is moved to the lowered position, the control device 25 is operated. Based on the signal, the second electric cylinder 22 operates the planting clutch 12 to the transmission cutoff side, and the control valve 21 and the hydraulic cylinder 6 operate the seedling planting device 5 to descend. Then, when the operation lever 24 is operated to the neutral position, the planting clutch 12 is operated to the transmission cutoff side by the second electric cylinder 22 based on the operation signal of the control device 25, and the seedling planting plant is planted by the control valve 21 and the hydraulic cylinder 6. The device 5 is stopped at that position.

With the above-described structure, one planting stroke (the operating lever 24 is in the planting position, the rear wheel transmission 10 is in the standard state in which the shift gear 15 is engaged with the input shaft 14) is completed, and the aircraft is on the edge. When the operator reaches, the operator operates the operation lever 24 to the raised position to perform the transmission interruption operation of the planting clutch 12, stops the seedling planting device 5, and raises it from the rice field G.

When the transmission clutch 12 is shut off by operating the operating lever 24, the first electric cylinder 18 is actuated by an operating signal from the control device 25, and the shift gear 15 engaged with the input shaft 14 is moved. , Is slid to the left side of the drawing and meshes with the first transmission gear 17. As a result, the rear wheel 2 is driven at a lower speed than the front wheel 1, and the rear wheel decelerates. In this way, the steering wheel 23 of FIG. 1 is operated to steer the front wheels 1 while the rear wheels 2 are being driven at a lower speed than the front wheels 1 to make a turn at the edge. In this case, at the same time, a side brake (not shown) may be applied to brake the rear wheel 2 on the center side of turning to make a turn.

As described above, when the turning at the edge of the ridge is completed and the machine body faces the direction of the next planting stroke, the operating lever 24 is operated from the ascending position to the descending position to the planting position, and the seedlings are planted. The planting device 5 is moved down to the field G. As a result, the planting clutch 12 is operated to the transmission side by the first electric cylinder 18, the seedling planting device 5 starts the planting operation, and the seedling planting device 5 is supported at the set height from the rice field G. Then, the seedling planting device 5 starts to be automatically moved up and down. At the same time, in response to an operation signal from the control device 25, the first electric cylinder 18
Stops its operation, and the shift gear 15, which is engaged with the first transmission gear 17, is slid rightward on the paper surface by the urging force of the spring 16 and is engaged with the input shaft 14. As a result, the front wheel 1
Then, the rear wheels 2 return to the standard state in which they are driven at substantially the same speed.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

[Fig. 1] Overall side view of the riding rice transplanter

FIG. 2 is a schematic plan view showing a transmission structure for front and rear wheels, a rear wheel transmission, etc.

[Explanation of symbols]

 1 Front Wheel 2 Rear Wheel 5 Ground Working Device 10 Rear Wheel Transmission 12 Work Clutch 18 Switching Means

Claims (1)

[Claims] 1. A standard state in which a front wheel (1) and a rear wheel (2) for traveling are driven at substantially equal speeds, and a rear wheel (2) is driven at a lower speed than the front wheel (1). This work is equipped with a rear wheel transmission (10) that can be switched between a wheel deceleration state and a work clutch (12) for performing transmission and transmission interruption operations to a ground work device (5) supported by the machine body. A four-wheel drive type paddy work vehicle provided with switching means (18) for switching the rear wheel transmission (10) from a standard state to a rear wheel deceleration state in conjunction with a transmission interruption operation of a clutch (12).