JPH09238508A - Farm tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the distance of a plowed part which is insufficient in plowing depth when a rotary plowing device is lowered while a tractor body travels fast. SOLUTION: This tractor is equipped with an elevation controller 40 which performs automatic plowing depth control for elevating and lowering a rotary tilling device so that the measurement signal of a grounding sensor 26 is held at a specific value and control for fast lowering in the beginning of the lowering of the rotary plowing device that is not grounded until switching height is measured by a tractor body height sensor 29 and then lowering in a speed reduced state after the switching height is reached, and also equipped with a height changing means E which sets the switching height higher and higher as the tractor speed measured by a tractor speed sensor 39 is higher and higher and a speed changing means F which makes the lowering speed in the speed reduced state higher and higher as the tractor speed measured by the speed sensor 39 is faster and faster.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-to-vehicle height sensor for connecting a rotary tiller to a traveling vehicle so that the rotary tiller can be moved up and down by driving an actuator, and measuring the height of the rotary tiller to the vehicle. It is equipped with a ground sensor that measures the height above the ground with respect to the ground surface behind the rotary tiller, and the rotary tiller is moved up and down by driving the actuator so that the measurement signal from the ground sensor is maintained at a predetermined value. In addition to performing automatic tillage control to maintain the rotary tiller at the beginning of descent of the rotary tiller in a non-grounded state, the rotary tiller is turned on by the height-to-body height sensor until the rotary tiller measures a predetermined height against the body. The present invention relates to an improvement of an agricultural tractor equipped with an elevating control device that descends at a high speed and, after reaching the height against the vehicle body, descends the rotary tiller in a decelerated state.

[0002]

2. Description of the Related Art Conventionally, there is an agricultural tractor constructed as described above, which is disclosed in Japanese Patent Application Laid-Open No. 4-75506. In this conventional example, the aforementioned control is performed when the rotary tiller is lowered. Compared with the one that lowers at a constant speed, it is a good aspect to reduce overload on the engine when the plowing claw of the rotary tiller touches the ground, reduce dashing, and reduce the amount of rise of plowing soil. It has become.

[0003]

However, in the control operation of this conventional example, the descending speed of the rotary tiller changes as described above regardless of the traveling speed of the vehicle body, so that, for example, in the case where the vehicle is traveling at high speed, When the descending control is performed, it takes a long time to reach the target tillage depth, and as a result, the tillage portion at an insufficient tillage depth also becomes longer and there is room for improvement.

An object of the present invention is to rationalize an agricultural tractor capable of shortening the length of a plowing part at an insufficient plowing depth even when the vehicle body is traveling at high speed during plowing work with a rotary tiller. There is a point in configuring.

[0005]

A first feature of the present invention (claim 1) is, as described at the beginning, a body of a rotary tiller which is connected to a traveling vehicle body by an actuator so as to be movable up and down. It is equipped with a height sensor against the vehicle body that measures the height, and a ground sensor that measures the height above the ground after plowing at the rear of the rotary tiller, and the measurement signal from the ground sensor is set to a predetermined value. The automatic tillage depth control is performed to maintain the tillage depth by raising and lowering the rotary tiller by driving the actuator so that the rotary tiller is detected by the height sensor against the vehicle body at the initial stage of descending the rotary tiller not in contact with the ground. Agricultural equipment provided with a control device for lowering the rotary tiller at a high speed until a predetermined height against the vehicle body is measured and, after reaching the height against the vehicle body, lowering the rotary tiller in a decelerating state. The tractor is provided with a speed sensor for measuring the traveling speed of the traveling vehicle body, and the higher the speed measured by this speed sensor, the higher the value of the height against vehicle body that is switched from the high speed descending state to the low speed descending state during the descending control Even if the height changing means is changed to the height changing means and the position is changed to the higher side by the height changing means, the time from the start of the descending until the rotary tiller touches the ground is shortened as compared with the case of low speed traveling. A speed changing means for increasing the descending speed of the rotary tiller during the descending control up to the speed set to the value is provided, and its operation is as follows.

A second feature of the present invention (claim 2) is to set the raising control in the automatic tilling depth control when the rotary tiller is lowered by the lowering control to switch to the automatic tilling depth control. In addition to being equipped with regulation means to block only time,
The faster the speed measured by the speed sensor is, the more the time changing means for shortening the set time in the restricting means is provided, and the operation thereof is as follows.

A third feature of the present invention (claim 3) is that the actuator comprises a hydraulic cylinder and the speed changing means controls the hydraulic cylinder as the speed measured by the speed sensor increases. Is configured to perform a control operation for increasing the supply / discharge amount of the hydraulic oil within a unit time, and its operation is as follows.

[Operation] According to the first feature described above, when lowering the rotary tiller, the higher the speed measured by the speed sensor, the higher the value of the height relative to the vehicle body that is switched from the high speed descending state to the low speed descending state. While changing the height changing means to a higher side, the rotary tiller is lowered at a faster speed, and this lowering speed shortens the time from the start of descending until the rotary tiller touches the ground as compared with low speed traveling. Since the value is set, the rotary tiller is brought into contact with the ground in a short time as compared with the case of low speed traveling, and it is possible to suppress the phenomenon that the plowing part becomes long at an insufficient plowing depth. Further, although the lowering speed in the low speed descending state becomes faster as the traveling speed of the vehicle body becomes faster, by changing the switching position from the high speed descending state to the low speed descending state to the higher side and increasing the descending stroke, The influence of the dynamic inertia of the rotary cultivator after the changeover is reduced to enable the descending at a desired deceleration speed.

According to the second feature, although the rotary tiller apparatus apparently reaches the target tilling depth by the measurement result of the ground sensor immediately after the automatic tiller depth control is switched by the lowering of the rotary tiller, ( The actual plowing depth is deeper than the target plowing depth.) Actually, the grounding sensor measures the field scene where the rise in the early stage of plowing is insufficient. Until the field scene of the state is formed, it is preferable to maintain the ground height of the rotary tiller, but in the case of regulating the constant time rise control regardless of the traveling speed, the tilling part deeper than the target tillage depth is required. It will be formed long. According to the present invention, when the traveling speed is increased, the regulation time of the regulation means for regulating the rising control in the automatic plowing depth control is shortened as the traveling speed becomes faster, so that the field scene sufficiently swelled by plowing can be set. It becomes possible to switch to the automatic tilling depth control in a short time while the ground sensor measures.

According to the third feature, the speed changing means controls the supply / discharge amount of the working oil of the control valve to the hydraulic cylinder as the actuator within a unit time so as to increase as the traveling speed of the vehicle body increases. Even when the speed is increased, it is possible to operate the rotary tiller as required by supplying and discharging a sufficient amount of hydraulic oil.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an engine 4 is arranged at a front part of a vehicle body 3 having a front wheel 1 and a rear wheel 2,
A transmission case 5 to which the power from the engine 4 is transmitted is disposed at the rear of the vehicle body 3.
A driver's seat 7 is arranged at an intermediate position between the left and right rear fenders 6 above the vehicle, a steering handle 8 is arranged in front of the driver's seat 7, and a two-point link mechanism 9 is provided at a rear end position of the vehicle body 3. A single-acting lift cylinder 1 in which a rotary cultivator 10 is connected to be movable up and down and to be rolled, and is arranged at an upper position of the mission case 5.
A pair of left and right lift arms 12 that are vertically moved by driving 1 (an example of the actuator of claim 1) and a two-point link mechanism 9 are connected to each other via left and right lift rods 13 to support them in a suspended state. By mounting a double-acting rolling cylinder 14 on one of the lift rods 13, an agricultural tractor which can freely drive and elevate the rotary tiller 10 and drive and roll around the rolling axis X in the front-rear direction is configured. To do.

As shown in FIG. 2, a rotary tiller 10 is provided.
The hydraulic system for driving up and down and driving rolling includes a hydraulic pump P driven by the engine 4, a flow priority valve 17 for flow control, and a control flow from the flow priority valve 17 for rolling. It comprises a rolling solenoid valve 18 for supplying to the cylinder 14 and an electromagnetic proportional control valve V for supplying surplus flow from the flow priority valve 17 to the lift cylinder 11 or discharging oil from the lift cylinder 11. The electromagnetic proportional control valve V includes a first valve 19 for ascending control,
Second valve 20 for pilot pressure control for opening and closing valve 19
And a third valve 21 for lowering control, a fourth valve 22 for pilot pressure control for opening and closing the third valve 21, and a relief valve 23. A current is supplied to the electromagnetic solenoid 20A of the second valve 20, and the first valve 19 is controlled by adjusting the supplied current.
As a result of the change in the pilot pressure acting on the valve, an opening of the valve that is proportional to this current value is obtained, and an ascending speed that is proportional to the opening is obtained. Further, when the rotary tiller 10 is controlled to descend. Supplies a current to the electromagnetic solenoid 22A of the fourth valve 22, and by adjusting the supplied current, the pilot pressure acting on the second valve 20 changes, and as a result, an opening degree of the valve proportional to this current value is obtained. The descending speed proportional to the opening is obtained.

In this agricultural tractor, the rotary tiller 1
Automatic tillage depth control for maintaining 0 at a predetermined height based on a field scene (ground), position control for raising and lowering the rotary tillage device 10 to a predetermined height based on the vehicle body 3, and a rolling shaft in a front-back posture. Rotary tilling device 10 around core X
And the rolling tillage device 10 is maintained at a predetermined rolling posture, and the rotary tillage device 10 is raised to a predetermined height with respect to the vehicle body in preference to the three types of control. And a control system for performing forced ascent control for setting and maintaining the rolling posture.

In addition, the driver's seat 7 is controlled so that automatic plowing depth control is performed.
The control box 24 is provided on the upper surface of the rear fender 6 on the right side of the vehicle, and the control box 24 is provided with a potentiometer-type tillage depth setting device 25. Rear cover 10 configured to be swingable about axis Y
A potentiometer-type grounding sensor 26 that measures the ground height of the rotary tillage device 10 based on the field scene (ground surface) after plowing from the swing amount of A is provided. At the base end of a lift lever 27 disposed on the right side of the driver's seat 7 is provided a potentiometer type position setting device 28, and at the base end of the lift arm 12, a rotary tilling device 10 is provided based on the swing amount of the lift arm 12.
Type lift arm sensor 29 for measuring the height of the vehicle relative to the vehicle (an example of the height sensor relative to the vehicle of claim 1)
In order to perform rolling control, the control box 24 is provided with a potentiometer-type rolling angle setter 30, and a rear end portion of the vehicle body 3 is provided with an electric amount of rolling in the left-right direction of the vehicle body 3. Is equipped with a rolling sensor 31 for measuring, and a stroke sensor 32 for measuring the amount of expansion and contraction of the rolling cylinder 14 is provided in the vicinity of the rolling cylinder 14, and as shown in FIG. Steering wheel 8
In the post portion 33, a forcible elevating lever 34 that is operable in the vertical direction and is biased to restore to the neutral position N and that is operable in the ascending position U and the descending position D is arranged. The base end is provided with a forced elevating switch 35 for detecting the operating direction of the lever 34. Further, in this agricultural tractor, as shown in FIG. 4, the traveling speed of the vehicle body is measured from the rotation speed of the input shaft 38 of the differential device 37 that transmits power to the rear wheels 2 from the gear type transmission device 36 incorporated in the mission case 5. A speed sensor 39 of a pickup type that is sensitive to the teeth of the gear is provided, and the speed sensor 39 lowers the rotary tiller 10 that has been raised to approximately the upper limit by the forcible raising control and switches to the automatic tilling depth control as described later. At this time, it is used for changing the control operation and setting the control sensitivity of the automatic plowing depth control.

As shown in FIG. 5, a system to which the signal from the setting system and the signal from the feedback system are input,
The control device 40 is configured to include a system that outputs a control signal to the electromagnetic proportional control valve V and the rolling electromagnetic valve 18. In addition, the outline of the automatic tilling depth control is that the lift cylinder 11 is driven so that the rotary tiller 10 is moved up and down so that the measured value from the ground sensor 26 changes toward the target tilling depth value set by the tiller depth setting device 25. At the same time, when the measured value from the ground sensor 26 reaches the signal zone of the dead zone set with the target tillage depth as a reference, the operation is set so as to stop the lifting and lowering of the rotary tiller 10, and the position control is performed. The outline is that the lift tiller 11 is driven to raise and lower the rotary tiller 10 so that the signal from the lift arm sensor 29 changes toward the target height value set by the position setter 28, and the target height is used as a reference. When the signal from the lift arm sensor 29 reaches the signal zone of the set dead zone, the operation of stopping the lifting and lowering of the rotary tiller 10 is set. Overview-ring control rotary tiller 1 set by the rolling angle setter 30
The target length of the rolling cylinder 14 is obtained based on the ground rolling angle of 0 and the horizontal rolling angle of the vehicle body 3 measured by the rolling sensor 31, and the stroke sensor 32 moves toward this target length value. The operation is such that the rolling cylinder 14 is driven so that the measured value changes, and the rolling control is stopped when the signal from the stroke sensor 32 reaches the signal range of the dead zone set based on the target length. The outline of the forced raising control is to operate the forced raising / lowering lever 34 to the raising position U until the signal from the lift arm sensor 29 reaches the dead zone signal range set based on the preset upper limit value. When the rotary tiller 10 is tilted with respect to the vehicle body 3 by the rolling control while raising 10 Is to drive the rolling cylinder 14 until it reaches a posture without inclination with respect to the vehicle body 3, and when the forcible lifting lever 34 is operated to the lowered position D, the height before the forced lifting control is performed (the automatic plowing depth control When the forcible ascent is performed in this state, control is performed to lower the rotary tiller 10 to a height at which automatic tillage depth control is performed).

Further, this agricultural tractor is constructed so as to be capable of automatic tilling depth control in a relatively high-speed traveling state of 3 to 4 km / hour (the conventional limit is about 1.8 km / hour). When the vehicle body 3 reaches a ridge at the time of plowing work under the tilling depth control, and the operation of the forcible lifting lever 34 raises the rotary tilling device 10 to invert the vehicle body 3 and lower the rotary tilling device 10. Is configured to perform a control operation of rapidly lowering the rotary tiller 10 to a working depth in which the working efficiency is not reduced and the automatic working depth control is restarted without reducing the overload.

That is, as shown in the flow chart of FIG. 6, the rotary tiller 10 is forcibly raised and the vehicle body 3
When the forced raising / lowering lever 34 is operated to the lowered position D after the turning of No. 1 is completed, the control parameter is set based on the measurement result of the speed sensor 39, and the rotary tiller 10 is forcibly lifted automatically. The switching height is set by calculating a predetermined value based on the measured value from the ground sensor 26 and the measured value from the lift arm sensor 29 during the tilling depth control, based on the control parameter. The electromagnetic proportional control valve V is set to the fully open position at the lowered position and the descent of the rotary tiller 10 is started (# 101
~ Step # 103).

This switching height is a height set with reference to the vehicle body 3 in order to switch the rotary tiller 10 from the high speed descending state to the decelerating descending state, and is measured from the ground sensor 26 during the automatic plowing depth control. A process for obtaining the relative distance between the vehicle body 3 and the farm scene is performed from the measured value and the lift arm sensor 29. Based on the processing result and the traveling speed of the vehicle body 3 based on the speed sensor 39, the higher the vehicle speed, the higher the switching height. By performing the calculation based on the control parameter so that the value is set high, even if the wheels 1 and 2 sink in the field scene, the tillage claw 10B of the rotary tiller 10 is separated from the position above the field scene. It is supposed to start decelerating. In this way, the height changing means E of claim 1 is constituted by step # 102 as a control operation for setting the switching height higher as the vehicle speed becomes faster.

As described above, after the rotary tiller 10 starts descending at a high speed, a signal from the lift arm sensor 29 is input to determine whether the rotary tiller 10 has reached the switching height, and at the same time, the switching height is increased. When it reaches the predetermined value, the electromagnetic proportional control valve V is throttled to the opening degree corresponding to the control parameter to start deceleration (steps # 104 to # 106).

The reason for lowering the speed in the decelerating state is that the load on the engine 4 is not sharply increased, and the speed thus decelerated is set so as to increase as the traveling speed becomes higher. The rotary cultivator 10 has a high switching height.
The length of the plowing trace at an insufficient plowing depth is shortened by determining the value of the descending speed in the deceleration state so that the time from the start of descending of the vehicle to the touchdown becomes shorter as the traveling speed of the vehicle body 3 becomes faster. It is supposed to do. The speed changing means F of claim 1 is constituted by step # 106 as a control operation for increasing the descending speed in the decelerated descending state as the traveling speed becomes faster.

Next, the rotary tiller 10 is moved downward.
After the plowing claw 10B of No. 1 comes into contact with the field scene, a region raised by plowing is formed in the field scene behind the rotary tiller 10, and the rear cover 10A of the rotary tiller 10 comes into contact with this site. Since it swings in the lifting direction, a signal from the ground sensor 26 is input to determine whether the rotary tiller 10 has descended to the working depth set by the working depth setting device 25. Then, when this signal reaches the target value in the automatic tilling depth control (strictly, it reaches the dead zone set based on the target value), the ascending control corresponds to the control parameter. The automatic tilling depth control, which is not performed only for the time, is started, and when this time elapses, the automatic tilling depth control is switched to (steps # 107 to # 109, step # 200). In step # 109 of this control operation, the restriction means G for preventing the rising operation of the rotary tiller 10 immediately before switching to the automatic tillage depth control in claim 2, and the restriction time shortened as the traveling speed increases. A time changing means H is configured.

Further, the time for restricting the ascending control by the automatic plowing depth control is set to 2 seconds when the vehicle body 3 travels at a low speed of 1.8 km / hour, and the higher the traveling speed, the more restricted the travel speed is. It is set to be inversely proportional to the traveling speed so that the time can be shortened.

As shown in the flow chart of FIG. 7, in the automatic tilling depth control, the signal from the tilling depth setting device 25 is input to calculate the target tilling depth (steps # 201, # 202), and the signal from the vehicle speed sensor is used. To set the width of the dead zone formed on the basis of the target plowing depth in proportion to the vehicle speed so that it becomes wider as the vehicle speed becomes higher, and is also discharged and supplied via the electromagnetic proportional control valve V. Set the hydraulic oil amount so that it decreases as the vehicle speed increases (# 203 to # 205).
Steps).

The reason for setting the width of the dead zone wider as the vehicle speed increases and limiting the amount of hydraulic oil supplied to and discharged from the lift cylinder 11 as the vehicle speed increases is that the rotary is used during high-speed traveling. Although it is ideal to raise and lower the tiller 10 at high speed in order to improve the followability to the field scene, it is difficult to control the rotary tiller 1, which is a heavy object, to move up and down at high speed, and there is an overshoot. Also, hunting may occur due to control delay, and for the purpose of eliminating these inconveniences, set the width of the dead zone wide as described above to limit the amount of hydraulic oil supplied to and discharged from the lift cylinder. The control sensitivity is lowered by and the hunting is avoided by moving up and down at low speed.

Next, the signal from the ground sensor 26 is input, and it is judged whether this signal is included in the signal range set in the dead zone. If not, the signal from the ground sensor 26 is located in the dead zone. Driven by the lift cylinder 11 via the electromagnetic proportional control valve V, the rotary tiller 10 is moved up and down, and when the signal from the ground sensor 26 reaches a state included in the signal zone of the dead zone, the elevator control is performed. It is to be stopped (steps # 206 to # 208).

Since the dead zone is set and the amount of hydraulic oil is set during the ascending / descending operation, the control sensitivity becomes slower and the control operation becomes slower as the vehicle speed becomes higher.

[Other Embodiments] In addition to the above-described embodiments, the present invention can use, for example, a dedicated sensor for measuring the amount of subsidence of the wheel with respect to the field scene in order to set the switching height. It is also possible to set the control operation to gradually close the opening of the valve so as to reduce the descending speed with a preset characteristic when the switching height is reached when the rotary tiller descends. is there.

[0028]

Therefore, even when the vehicle body is traveling at a high speed during the plowing work with the rotary tiller, the plowing portion is shortened at an insufficient plowing depth to quickly and properly plowing. An agricultural tractor that can be transferred to plowing work has been rationally constructed (claim 1). Further, by increasing the descending speed, the rotary tiller can quickly switch to the automatic plowing depth control by taking advantage of the good surface of reaching the proper plowing depth in a short time (Claim 2). By changing the amount, it becomes possible to control the raising and lowering of the rotary cultivator which corresponds to the increase of the traveling speed (claim 3).

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings.

[Brief description of drawings]

FIG. 1 is a side view of an agricultural tractor.

[Fig. 2] Hydraulic circuit diagram for lifting and rolling

FIG. 3 is a side view showing the arrangement of the forcible lifting lever.

FIG. 4 is a schematic diagram of a transmission system showing an arrangement of speed sensors.

FIG. 5 is a block circuit diagram of a control system.

FIG. 6 is a flowchart of a descent control operation.

FIG. 7: Flow chart of automatic plowing depth control

[Explanation of symbols]

 3 Traveling vehicle 10 Rotary tiller 11 Actuator 26 Grounding sensor 29 Height sensor against vehicle 39 Speed sensor 40 Lifting control device E Height changing means F Speed changing means G Regulation means H Time changing means V Control valve

Claims (3)

[Claims] 1. A rotary tiller (10) which is movable up and down by driving an actuator (11) with respect to a traveling vehicle body (3).
And a height sensor (29) for measuring the height of the rotary tiller (10) with respect to the vehicle body, and a ground surface based on the ground surface after plowing behind the rotary tiller (10). A grounding sensor (26) for measuring the height, and the rotary tiller (1) is driven by driving the actuator (11) so as to maintain the measurement signal from the grounding sensor (26) at a predetermined value.
0) is moved up and down to maintain the tilling depth, and at the beginning of the descent of the rotary tiller (10) in the non-grounded state, the rotary tiller (10) with the height sensor (29) against the vehicle body is used. Is lowered at a high speed until a predetermined height against the vehicle body is measured, and after reaching the height against the vehicle body, a descending control for lowering the rotary tiller apparatus (10) in a decelerated state is performed. An agricultural tractor having a control device (40) for performing, comprising a speed sensor (39) for measuring the traveling speed of a traveling vehicle body, and the higher the speed measured by the speed sensor (39), the more the lowering control is performed during the lowering control. The height changing means (E) for changing the value of the height relative to the vehicle body for switching from the high speed descending state to the low speed descending state, and the position from the position thus changed to the high side by the height changing means (E). Compared to low speed running even when descending And speed changing means (F) for increasing the descending speed of the rotary tiller (10) during the descending control to a speed set to a value that shortens the time from the start of descending until the rotary tiller (10) touches the ground. Agricultural tractor equipped with. 2. A rotary tiller (1) according to the descending control.
0) is lowered to switch to the automatic plowing depth control, the restraint means (G) is provided for blocking the rising control in the automatic plowing depth control for a set time, and the speed measured by the speed sensor is The agricultural tractor according to claim 1, further comprising a time changing means (H) for shortening a set time in the restricting means (G) as the speed increases. 3. The actuator (11) is composed of a hydraulic cylinder, and the speed changing means (F) is
The control operation according to claim 1, wherein the control operation is performed such that the higher the speed measured by the speed sensor (39), the larger the supply / discharge amount of the working oil of the control valve (V) to the hydraulic cylinder per unit time. Agricultural tractor.