JPH09238507A - Farm tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tractor which finishes a field surface flatly after plowing even when a tractor body travels fast on the field surface. SOLUTION: This tractor is equipped with a control mode changing means E which suppresses the feed and discharge amounts of working fluid in each unit time of a control valve 18 to and from a hydraulic cylinder 14 or increases the width of a dead zone set on the basis of target plowing depth so as to suppress the rolling operation of a plowing device under automatic rolling control as a rolling frequency measured by a rolling sensor 31 increases or a rolling angle increases while the travel speed of the tractor traveling body measured by a speed sensor 39 is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilling apparatus which is connected to a traveling vehicle body in a rolling manner by driving an actuator, and drives the actuator based on a signal from a rolling sensor for measuring a rolling angle of the traveling vehicle body. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural tractor provided with a control device capable of performing rolling control for maintaining a rolling posture of a tilling device, and more particularly, to an improvement in technology for changing a form of rolling control.

[0002]

2. Description of the Related Art Conventionally, there is an agricultural tractor constructed as described above in Japanese Patent Publication No. Hei 6-71363. In this conventional example, a dead zone width of a rolling control is changed based on a vehicle speed, and a rolling cylinder is used. It is configured to change the form of the rolling control by adjusting the operating speed of.

[0003]

In a plowing operation with a tractor equipped with a tilling device, when a control for maintaining the tilling device in a predetermined rolling posture is performed, a rolling sensor for measuring a rolling angle of a traveling vehicle body is used. Is controlled based on the signal of (1) to drive the actuator so that the tillage device maintains a predetermined ground rolling posture. Further, the control for rolling the tilling device by driving the actuator in this way is caused by a phenomenon in which one wheel falls into a recess such as a rut in the field, or one wheel rides on a protrusion such as a clod in the field. To do.

Further, when rolling the tilling device when the posture of the vehicle body changes, the rolling operation of the tilling device quickly in conjunction with the speed of the fluctuation of the vehicle body posture can maintain the posture of the tilling device with respect to the field. However, in reality, rolling a heavy tiller at high speed requires not only a large-capacity actuator, but also when a heavy tiller is operated at high speed. It is also difficult to suppress the overshoot of the cultivator, and it is difficult to control the tilling apparatus to maintain an appropriate posture.
Particularly, when the rolling control is performed at the same time as the plowing operation by running the body at high speed in a rough field, the body frequently shakes in a short period of time, and the body shakes as if bouncing. The amplitude is also large. In such a situation, when the tillage device is rolled at a high speed for the purpose of maintaining the predetermined rolling posture, not only the above-described overshoot but also a control for maintaining an appropriate rolling posture due to the influence of the control delay. It is difficult to perform, for example, when the right side of the tillage device is to be driven in the upward direction, a phenomenon in which the right side is lowered is performed. There is room.

An object of the present invention is to provide an agricultural tractor capable of suppressing useless operation of rolling control and flattening a plowed field scene even when a vehicle is driven at high speed in a rough field to perform work. The point is to construct it rationally.

[0006]

According to a first aspect of the present invention, as described at the outset, a tillage device is connected to a traveling vehicle body in a rolling manner by driving an actuator to the traveling vehicle body. A farm tractor equipped with a control device capable of performing a rolling control to maintain a rolling posture of a tilling device by driving an actuator based on a signal from a rolling sensor that measures a rolling angle, and measures a traveling speed of a traveling vehicle body. A speed sensor, the speed measured by the speed sensor increases, and the rolling frequency measured by the rolling sensor increases, or as the rolling angle measured by the rolling sensor increases, the rolling A control mode changing means for changing the control mode in a direction to suppress the rolling operation in the control. Yes, the action is as follows.

A second feature (claim 2) of the present invention is that the actuator is constituted by a hydraulic cylinder, and the control mode changing means controls the rolling operation of the tilling apparatus in the rolling control in a direction for suppressing the rolling operation. When the mode is changed, the control operation for reducing the supply / discharge amount of the operating oil of the control valve to the hydraulic cylinder per unit time is performed, and the operation is as follows.

A third feature of the present invention is that the rolling control is performed such that the rolling control is performed when the measured value of the rolling sensor deviates from a dead zone set on the basis of a control target. The mode is set, and the control mode changing means is configured to perform a control operation for expanding a dead zone of the rolling control when changing the control mode in a direction to suppress the rolling operation in the rolling control. The effect is as follows.

A fourth feature of the present invention (claim 4) is that the rolling control performs control as a measured value using a value obtained by averaging a predetermined number of signals taken at predetermined time intervals from the rolling sensor. When the control mode changing means changes the control mode in a direction to suppress the rolling operation in the rolling control, the number of signals to be fetched at predetermined time intervals from the rolling sensor at the time of the rolling control and to be averaged is determined. It is configured to perform an increasing control operation, and its operation is as follows.

According to the first feature, when the traveling speed of the traveling vehicle body is increased, the rolling frequency measured by the rolling sensor increases, or the rolling angle measured by the rolling sensor increases. The more the control mode changing means changes the control mode in a direction to suppress the rolling operation of the tilling device, and the rolling operation of the tilling device is suppressed even if the cultivating device reaches a rolling angle that requires rolling. . In other words, when the traveling speed of the traveling vehicle increases, the rolling angle and the rolling frequency of the vehicle increase, which means that the number of irregularities in the field scene per unit traveling distance is large, or the height difference of the irregularities is large. In such a case, it is difficult to roll the tilling device following the rolling of the vehicle body that occurs frequently, so by slowing down the rolling operation without actively performing the control to follow the rolling, This prevents the tilling device from rolling in an inappropriate direction due to overshoot or control delay, thereby flattening the field scene after tilling.

According to the second feature, when the control mode is changed in a direction to suppress the rolling operation of the tilling apparatus, the supply and discharge of the hydraulic oil per unit time at the control valve is reduced, so that the operating speed is reduced. Is reduced to prevent an excessive rolling operation.

According to the third feature, when the control mode is changed in a direction to suppress the rolling operation of the tillage device, the dead zone is expanded, and the measurement result from the rolling sensor deviates from the control target. Also in this case, the control is started when the deviation amount becomes larger, and the control ends in a state where the deviation amount is large. That is, since the control start tends to be delayed and the control end tends to end earlier, the sensitive rolling operation is prevented.

According to the fourth feature, even if the rolling value measured by the rolling sensor within a unit time deviates from the control target due to the rolling of the vehicle body, the control target is averaged from the current rolling posture of the tilling device when averaging. There is a tendency for the deviation to the rolling posture to be small, and the number of measurements (sampling number) within this unit time
By increasing the value, it becomes possible to further reduce the above-mentioned deviation, thereby preventing a sensitive rolling operation.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, an engine 4 is disposed at a front portion of a vehicle body 3 having a front wheel 1 and a rear wheel 2, and a transmission case 5 to which power from the engine 4 is transmitted is provided at a rear portion of the vehicle body 3. The driver's seat 7 is disposed at an intermediate position between the left and right rear fenders 6 above the transmission case 5, the steering handle 8 is disposed at the front of the driver's seat 7, and the driver's seat 7 is located at the rear end of the vehicle body 3. The rotary tilling device 10 is connected to the rotary tilling device 10 so as to be able to move up and down and rolling freely via the two-point link mechanism 9, and is operated by a single-acting lift cylinder 11 disposed at an upper position of the transmission case 5. The pair of lift arms 12 and the two-point link mechanism 9 are connected to each other via the left and right lift rods 13 so as to be supported in a suspended state. Linda 14
By interposing (an example of the actuator of the first aspect), an agricultural tractor in which the drive up and down of the rotary tillage device 10 and the drive rolling around the rolling axis X in the front-rear direction can be freely configured.

[0015] As shown in FIG.
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, the opening of the valve proportional to the current value is obtained, and the ascending speed is obtained in proportion to the opening. Has an electromagnetic solenoid 22A of the fourth valve 22
While supplying current to the
As a result of the change in the pilot pressure acting on the second valve 20, an opening degree of the valve proportional to the current value is obtained, and a descending speed proportional to the opening degree is obtained.

In this agricultural tractor, the rotary tilling device 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.

Also, the driver's seat 7 is controlled so as to perform automatic plowing depth control.
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.
The control box 24 is provided with a potentiometer-type rolling angle setting device 30 so as to perform rolling control. A rolling sensor 31 for electrically measuring the amount of rolling of the vehicle body 3 in the left-right direction, a stroke sensor 32 for measuring the amount of expansion and contraction of the rolling cylinder 14 at a position near the rolling cylinder 14, and As shown in FIG. 4, the post portion 33 of the steering handle 8 is vertically operable so as to perform forced ascending control, and is urged to return to the neutral position N. Forced lifting lever 3 operable with D
4 is provided, and a forced lifting switch 35 for detecting the operation direction of the lever 34 is provided at the base end of the lever 34. Further, in this agricultural tractor, as shown in FIG. 5, a pickup type that measures the running speed of the vehicle body from the rotation speed of the input shaft 38 of the differential device 37 with respect to the rear wheels 2 from the gear type transmission 36 incorporated in the transmission case 5. The speed sensor 39 is used for setting the control sensitivity of the automatic plowing depth control and the automatic rolling control as described later.

As shown in FIG. 6, the tillage depth setting device 25,
Grounding sensor 26, position setting device 28, lift arm sensor 29, rolling angle setting device 30, rolling sensor 31, stroke sensor 32, forced lifting switch 3
5. The control device 40 includes a system for inputting a signal from each of the speed sensors 39, and a system for outputting control signals to the electromagnetic proportional control valve V and the rolling electromagnetic valve 18.

The outline of the automatic cultivation depth control is as follows.
The lift cylinder 11 is driven to move the rotary tillage device 10 up and down so that the measurement value from the ground contact sensor 26 changes toward the value of the target plowing depth set in the above, and the dead zone set based on the target plowing depth is set. When the measured value from the ground sensor 26 reaches the signal area, the operation is set so as to stop the raising and lowering of the rotary tilling device 10, and the outline of the position control is the same as the target height set by the position setting unit 28. The rotary tilling device 10 is moved up and down by driving the lift cylinder 11 so that the signal from the lift arm sensor 29 changes toward the value, and the signal from the lift arm sensor 29 is moved to the signal range of the dead zone set based on the target height. The operation of stopping the elevation of the rotary tillage device 10 when a signal is reached is set. The outline of the automatic rolling control is the rolling angle. A ground rolling angle of the rotary tiller 10 set in Joki 30, rolling sensor 31
The target length of the rolling cylinder 14 is obtained based on the rolling angle of the vehicle body 3 in the left-right direction measured by the above-described method, and the value of the rolling cylinder 14 is changed toward the value of the target length. 14 and an operation of stopping the rolling control when a signal from the stroke sensor 32 reaches a signal zone of a dead zone set based on the target length. By operating the lever 34 to the ascending position U, the rotary tiller 10 is raised until a signal from the lift arm sensor 29 reaches a signal range of a dead zone set based on a preset upper limit as a reference, and automatic rolling control is performed. When the rotary tilling device 10 is in a state of being inclined with respect to the vehicle body 3, it reaches a posture without inclination with respect to the vehicle body 3. Is intended to drive the rolling cylinder 14 to the lowering position D the forcible lift lever 34
To perform the control to lower the rotary tillage device 10 to the height before the forced ascent control is performed (to the height at which the automatic tillage control is performed when the forced ascent is performed in the automatic plowing control state). Has become.

Further, this agricultural tractor is configured to be capable of automatic plowing depth control in a relatively high-speed running state of 3 to 4 km / hour (conventionally, the limit is about 1.8 km / hour). When the vehicle body 3 is driven at a high speed in a field scene in which many irregularities due to ruts are formed like a headland and an automatic rolling control is performed simultaneously with an automatic plowing depth control, a plowing operation is performed. When the vehicle body 3 rolls a lot in a short time based on the above, or when the vehicle body 3 rolls a lot, the raising and lowering operation and the rolling operation in the automatic plowing depth control and the automatic rolling control are suppressed, so that the field after plowing is controlled. The surface is configured to be flat, and the control operation thereof will be described below.

When performing the automatic plowing depth control and the automatic rolling control, a parameter setting routine is executed prior to these controls to obtain data necessary for the control. That is, as shown in the flowchart of FIG. 7, first, a signal from the speed sensor 39 is input to determine whether the traveling speed of the vehicle body 3 is equal to or higher than the set value (Steps # 101 and # 102). In some cases, the rolling sensor 3
The signal from 1 is input and the number of times of rolling (frequency) per unit time and the rolling angle are measured, and it is determined whether any of them is greater than a set value. , The valve drive parameters and the dead zone parameters are set based on the table data, and the sampling parameters used for the automatic rolling control are set based on the table data (steps # 103 to # 107). Further, when the traveling speed of the vehicle body 3 measured by the speed sensor 39 is equal to or less than the set value, and when the rolling frequency (frequency) measured by the rolling sensor 31 per unit time and the rolling angle are both set values. If it is below, each of the valve drive parameter and the dead zone parameter is set to the initial value (# 108 step).

In step # 106, the table data for setting each of the valve drive parameter and the dead zone parameter includes a large measured value (vehicle speed) by the speed sensor 39, a measured value of the number of times of rolling (frequency), and a measured value of the rolling angle. The characteristic is set so as to reduce the flow rate of the hydraulic oil supplied / discharged by the electromagnetic proportional control valve V and at the same time expand the dead zone (width) (see the graph in the same step), and the number of rolling ( Frequency) or, if the rolling angle is greater than or equal to the set value, this rolling frequency,
Alternatively, when the valve drive parameter and the dead zone parameter are read out from the table data based on the rolling angle and the traveling speed of the vehicle body 3, and both the rolling frequency (frequency) and the rolling angle are equal to or more than the set values, the rolling is performed. Valve drive parameters and dead zone parameters are read from the table data based on the number of times (frequency), the rolling angle, and the traveling speed of the vehicle body.

Further, as the valve drive parameter increases, the power supplied to the electromagnetic proportional control valve V decreases as the number of rolling times (frequency) increases, as the rolling angle increases, or as the traveling speed increases. It is a numerical value for determining the duty ratio for reducing the opening degree of the valve V, and the dead zone parameter increases as the number of times of rolling (frequency) increases or as the rolling angle increases.
Alternatively, it is a numerical value for expanding the area (width) of the dead zone set based on the target plowing depth as the traveling speed increases.

In step # 107, the table data for setting the sampling parameters is such that the larger the measurement value (vehicle speed), the number of rolling times (frequency), and the measurement value of the rolling angle of the speed sensor, the larger the value in the unit time. The characteristic is set so as to increase the number of times of sampling. If the number of times of rolling (frequency) or the rolling angle is equal to or larger than a set value, the rolling frequency or the rolling angle and the traveling speed of the vehicle body 3 The sampling parameter is read from the table data based on the number of times (frequency) and the rolling angle are both equal to or greater than a set value, and based on the number of times of rolling (frequency), the rolling angle, and the traveling speed of the vehicle body. The sampling parameters are read from the table data.

In step # 108, the initial values set for each of the valve drive parameter and the dead zone parameter are preset numerical values. When the vehicle speed is low, or even when the vehicle speed is high, the number of times of rolling (frequency If the measured value of (1) and the measured value of the rolling angle are smaller than predetermined values, appropriate automatic lifting control and automatic rolling control are enabled.

As shown in the flowchart of FIG. 8, in the automatic tillage depth control, a signal from the tillage depth setting device 25 is input to set a target tillage depth, and based on the dead zone parameter based on the target tillage depth. Set the dead zone of the area (# 20
1, # 202 step) Further, a signal from the ground contact sensor 26 is input, and it is determined whether or not this signal value is set as described above and is within the dead zone of the target plowing depth. If the control is not performed and the power is outside the dead zone, the intermittent power of the duty ratio based on the valve drive parameter is changed to the electromagnetic proportional control valve V
, The tillage device is raised and lowered (steps # 203 to # 205).

As shown in the flowchart of FIG. 9, in the automatic rolling control, a signal from a rolling angle setting device is input, a measurement signal is input from a rolling sensor at a cycle based on the sampling parameter, and the measurement signal is averaged. Then, the target length of the rolling cylinder is calculated and obtained from the deviation between the processing result and the signal from the rolling setter (# 301 to # 304 steps).
In the averaging process, a sum of sampled data is obtained, and an average value is obtained by dividing (dividing) the value of the sum by the number of times of sampling.

Next, a dead zone of a range based on the parameter is set based on the target length, a signal from the stroke sensor 32 is input, and it is determined whether or not this signal value is within the dead zone of the target length. If it is within the dead zone, the rolling control is not performed, and if it is outside the dead zone, the intermittent power based on the valve drive parameter is supplied to the rolling solenoid valve 18 to perform rolling of the tilling device (#). 305 to # 208 steps). # 302, # 3
Steps # 04 and # 308 are an example of the control mode changing means E in claim 1. In step # 302, the rolling operation is suppressed by increasing the number of samplings (claim 4).
In the fourth step, the rolling operation is suppressed by expanding the dead zone (claim 3), and in the step # 308, the rolling operation is suppressed by reducing the amount of hydraulic oil supplied and discharged via the control valve ( Claim 2) It is set in the form.

As described above, according to the present invention, when the traveling speed of the vehicle body 3 is equal to or higher than the predetermined value, the degree of roughness (the degree of unevenness) of the field scene is determined based on the signal from the rolling sensor 31, and the roughness is severe. In this case, the start of the rolling operation of the rotary tilling device 10 is delayed as the degree of roughness is severe, and the rolling stroke of the rotary tilling device 10 is reduced by speeding up the end of the rolling operation, and the speed at the time of the rolling operation is reduced. As a result, the excessive rolling operation following the field scene is prevented by lowering the speed. As a result, the occurrence of overshoot is suppressed, and at the same time when the right side of the rotary tillage device needs to be raised, the rotary tillage device 10 The operation in the reverse direction, such as descending, is prevented, and the field scene after plowing can be flattened.

[Alternative Embodiment] In the above embodiment, the data for setting the opening of the valve and the data for setting the dead zone are obtained from preset table data. However, in the present invention, the traveling speed, the number of rolling ( Frequency) and the rolling angle. Further, it is also possible to implement the control mode changing means for suppressing the rolling operation by using only one of the processes for limiting the supply and discharge amount of the hydraulic oil or expanding the dead zone.

[0031]

Therefore, even when the vehicle is driven at high speed in a rough field and the work is performed, the agricultural tractor which suppresses useless operation of the rolling control and flattens the field scene after plowing is reasonable. (Claim 1). In addition, the rolling operation can be suppressed by reducing the speed by a simple means of changing the supply / discharge amount of the hydraulic oil through the control valve (claim 2), and by a very simple means of changing the electric processing. The rolling operation can be suppressed by changing the timing of starting and stopping the rolling operation (claim 3), and the rolling operation can be suppressed by an electrically simple process of increasing the number of samplings (claim 4).

Incidentally, reference numerals are written in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of drawings]

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

FIG. 2 is a rear view of the agricultural tractor.

FIG. 3 is a hydraulic circuit diagram of a lifting system and a rolling system.

FIG. 4 is a side view showing an arrangement of a forced lifting lever.

FIG. 5 is a schematic diagram of a transmission system showing an arrangement of a speed sensor.

FIG. 6 is a block circuit diagram of a control system.

FIG. 7 is a flowchart of a parameter setting routine.

FIG. 8 is a flowchart of automatic plowing depth control.

FIG. 9 is a flowchart of automatic rolling control.

[Explanation of symbols]

 Reference Signs List 3 traveling vehicle body 10 tillage device 14 actuator 18 control valve 31 rolling sensor 39 speed sensor 40 control device E control form changing means

Claims (4)

[Claims] 1. A rolling sensor (31) for measuring a rolling angle of a traveling vehicle body (3) by connecting a cultivating device (10) to the traveling vehicle body (3) by driving an actuator (14) so as to allow rolling. A control device (4) capable of performing a rolling control for maintaining the rolling posture of the tiller (3) by driving the actuator (14) based on the signal.
0) which is an agricultural tractor and which measures a traveling speed of a traveling vehicle body (3).
9), the speed measured by the speed sensor (39) increases, and the rolling frequency measured by the rolling sensor (31) increases, or the rolling sensor (31) measures. An agricultural tractor comprising a control form changing means (E) for changing the control form in a direction of suppressing the rolling operation in the rolling control as the rolling angle increases. 2. The actuator (14) is composed of a hydraulic cylinder, and the control form changing means (E).
However, when changing the control mode to the direction of suppressing the rolling operation of the tiller (10) in the rolling control, the control for reducing the supply / discharge amount of the hydraulic oil of the control valve (18) to the hydraulic cylinder per unit time. The agricultural tractor of claim 1, wherein the agricultural tractor is configured to operate. 3. The rolling sensor (3) starting from a dead zone in which the rolling control is set with reference to a control target.
When the control mode is set to perform the rolling control when the measured value of 1) is out of line, and the control mode changing means (E) changes the control mode in a direction of suppressing the rolling operation in the rolling control. The agricultural tractor according to claim 1, wherein the agricultural tractor is configured to perform a control operation for expanding a dead zone of the rolling control. 4. The rolling control is configured to perform control by using a value obtained by averaging a predetermined number of signals taken from the rolling sensor (31) at predetermined time intervals as a measured value, and the control mode. Change means (E)
When changing the control mode to suppress the rolling operation in the rolling control, the rolling sensor (31) is configured to perform a control operation to increase the number of signals to be averaged at a predetermined time interval during the rolling control. The agricultural tractor according to claim 1.