JPH10136710A - Load controller for tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the work of an excellent grading property by promptly grounding a work machine at the time of elevating the work machine by load control and then lowering it again and making load fluctuation after grounding small in a tractor provided with plowing depth control and load control. SOLUTION: At the time of lowering the work machine 18, it is lowered stepwise for one step each. In a first step, the work machine 18 is lowered for 1/2 of the difference of a highest position for which the work machine 18 is elevated by the load control and a position equivalent to a set plowing depth value first. Then, in a second step, the work machine 18 is lowered for 1/2 of the difference of the position lowered in the one step of a previous time and the position equivalent to the set plowing depth value, that is 1/2 of the remaining further from the first step. In such a manner, the work machine 18 is lowered stepwise for one step each until it is matched with the set plowing depth value and a lowering amount for each step is successively reduced as approaching the set plowing depth value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tractor load control device, and more particularly to a tractor load control device that raises and lowers a work machine when the engine speed fluctuates. .

[0002]

2. Description of the Related Art A working machine for tilling is connected to the rear of a machine body so as to be able to move up and down, and the working machine is adjusted so that an actual tillage depth value detected by a depth sensor coincides with a set tillage depth value. The tractor is provided with tillage depth control for raising and lowering the tractor and load control for determining the towing load of the work implement from the engine speed and raising and lowering the work implement so that the engine speed is maintained within a predetermined range. Have been.

When the engine speed is returned to a normal state and the work machine is lowered after the work machine is lifted by the load control, if the work machine is suddenly lowered and grounded, the load increases and the engine speed increases. The number will drop and the implement will rise again. In such a case, hunting occurs due to the working machine repeatedly rising and lowering, so that a large swell occurs in the field scene.

In order to prevent this, there is known a load control device in which the working machine is lowered step by step by taking a certain height as one step. However, when the set cultivation depth value is deep, the lowering operation of several steps to several tens of steps is required until the working machine reaches the set cultivation depth value,
It takes time to return to the original plowing position. On the other hand, if the set height of one step is too large in order to quickly return the work implement to the set work depth value, the work implement will be set to 1 when the set work depth value is shallow.
It may exceed the set tillage value just by stepping down, in which case the load increases rapidly and the work equipment rises,
It may cause hunting.

Therefore, in a tractor provided with tillage depth control and load control, when the work equipment is raised and lowered again by the load control, the work equipment is quickly brought into contact with the ground and the load fluctuation after the contact is reduced. However, there arises a technical problem to be solved in order to perform a work with good leveling property, and an object of the present invention is to solve this problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object, and a working machine for tilling is movably connected to the rear part of an airframe so that the actual cultivation depth detected by a depth sensor can be obtained. Tillage control that raises and lowers the work implement so that the value matches the set tillage value, and determines the traction load of the work implement from the engine speed, and works so that the engine speed is maintained within a predetermined range. In a tractor provided with a load control for raising and lowering the machine, when the work machine is lowered after a work machine lift command is output by the load control, the work machine is lowered step by step by one step, and An object of the present invention is to provide a load control device for a tractor in which the descending amount of one step is gradually decreased as the set cultivation depth approaches.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a tractor 10, in which an engine 11 is mounted in front of the tractor 10, and the engine 11
The electronic governor 12 is mounted on the side of the electronic governor. Engine 1
The motive power 1 is decelerated by a transmission provided in the transmission case 13 and is transmitted to the front and rear wheels 14a, 14b or the rear wheels 14b and also to the PTO shaft 15. The engine speed is controlled by an engine speed sensor 16.
Detect with.

On the other hand, a working machine 18 for tilling is connected to a rear portion of the tractor 10 via a link mechanism 17. The link mechanism 17 includes a top link 19 and left and right lower links 2.
This is a three-point link system consisting of zeros, and the ends of the left and right lift arms 21 and the left and right lower links 20 are connected by lift rods 22, respectively.

When the lift arm 21 is rotated by the operation of a lift cylinder 23 provided on the upper part of the transmission case 13, the lower link 20 moves up and down, and the work implement 18 moves up and down. The rotation angle of the lift arm 21 is detected by a lift arm sensor 24. Also, the working machine 18
The rear cover 26 is rotatably attached to the rear end of the main cover 25, and the rotation angle of the rear cover 26 is detected by the depth sensor 27.

A controller 29 is provided near the driver's seat 28. The controller 29 is provided with a position lever 30, a tillage setting dial 31, a load control mode switch 32, and the like. A vehicle speed sensor 33 is provided below the driver's seat 18. Further, a work implement lift switch 35 is provided near the steering wheel 34, and a steering angle sensor 37 is mounted on the steering shaft 36.

FIG. 2 is a block diagram of a tractor depth control and load control system.
Setting signals of the tillage setting dial 31, the load control mode switch 32, and the like are input to the controller 29. Further, detection signals from the engine speed sensor 16, the lift arm sensor 24, the depth sensor 27, the vehicle speed sensor 33, and the like are also input to the controller 29. In addition, the throttle operation amount of the electronic governor 12 is detected by a throttle position sensor 38 provided at the rotation base of the throttle lever, and the position of the control rack (the governor opening) is detected by a rack position sensor 39. Further, a shift position sensor 40 is provided in the transmission to detect a shift operation of a shift lever.

The controller 29 calculates the actual tillage depth value from the rotation angle of the rear cover 26 detected by the depth sensor 27, and matches this actual tillage depth value with the set tillage depth value input by the tillage depth setting dial 31. The working depth of the working machine 18 is controlled as described above. In this case, a control signal is output to the ascending solenoid 41 or the descending solenoid 42 of the solenoid proportional valve in order to move the work machine 18 up and down by extending and retracting the lift cylinder 23.

On the other hand, the control of the electronic governor 12 is controlled by a controller 29 in accordance with the value detected by the throttle position sensor 38.
Outputs a control signal to the rack actuator 43 to adjust the position of the control rack to control the engine speed. When the load control mode switch 32 is turned on, load control is performed as described later. At this time, the load control monitor lamp 44 is turned on to notify the operator that load control is being executed.

Next, the load control will be described. In order to determine the traction load of the work implement 18 from the engine speed, the controller 29 periodically detects the engine speed R by the engine speed sensor 16 and keeps it constant. The change rate D of the engine speed within time is calculated.

[0015] preliminarily decided specified value D _R of the engine speed lower limit L _R and the engine speed change rate corresponding to the set tilling depth value, decreases the engine speed R is gently by workload when it becomes less than the lower limit L _R outputs the working machine rises command to increase solenoid 41 from the controller 29, to prevent engine stall by raising the working machine 18.
Further, when the change rate D in the engine speed the engine speed R is sharply reduced is equal to or greater than the specified value D _R is, even when the engine speed R is not decreased to the lower limit L _R Then, the controller 29 outputs a work implement lift command to the ascending solenoid 41 to raise the work implement 18 to prevent engine stall.

Then, the work implement 18 is raised and the work load is reduced, so that the reduced engine speed R
Rises and returns to a predetermined value, or when the rate of change D of the engine speed decreases, the controller 2
The work implement lowering command is output from 9 to the lowering solenoid 42 to lower the work implement 18.

FIG. 3 is a flowchart showing a case where the plowing depth control and the load control are performed in combination.
In the case of, the process proceeds from step 102 to step 103, and when the load control is not “ON”, the tillage depth control is performed based on the detection value of the depth sensor 27 (step 103 → 10).
5) When the load control is “ON”, mix control of the plowing depth control and the load control is performed (step 103 → 1).
06).

On the other hand, if the tillage depth control is not "ON", the process proceeds from step 102 to step 104. If the load control is "ON", the load control is based on the detected value of the engine speed sensor 16. Perform load control (step 10
4 → 107), when the load control is not “ON”, the position control by the position lever 30 is performed (steps 104 → 108).

FIG. 4 is a flow chart of the load control in the mix control in the step 106 and the load control in the step 107. The rate of change of the engine speed from the engine speed R read in the step 101 is shown in FIG. D
Is calculated (step 201), and if the work implement raising command by the load control is not output, that is, if the normal work is continued and the load raising output is off, the process proceeds from step 202 to step 203.

[0020] As described above, when the engine speed R is equal to or less than the lower limit L _R by workload, or when the change rate D of the engine rotational speed is equal to or greater than the specified value D _R, the controller 29 , The work implement lift command is output to the lift solenoid 41, that is, the load rise output is turned on (steps 203 → 204).

If it is determined in step 202 that the load increase output is on, the load increase output is turned off. For example, the load-up output OFF process when the load increase output on when the engine speed R is equal to or less than the lower limit L _R, will be described in accordance with FIGS.
Due to an increase in the work load, the engine speed R is reduced to the lower limit L.
_{When the} output becomes lower than _R , the load increase output is turned on, and the work implement rises to reduce the load. However, immediately after the load increase output is turned on, the engine speed R continues to decrease. The conversion to rise after the engine speed R reaches a minimum value R _B (step 301). Storing the minimum value R _B of the engine speed at this time in the memory (step 302).

If only the load control is being executed, the process proceeds from step 303 to step 304, where the engine speed R
There several turns than the minimum value R _B alpha (approximately 50-100 rpm)
When the load increases, the load increase output is turned off (step 304 → 305), and the lift arm sensor value at this time is stored in the memory (step 306). The engine rotational speed R is given to turn off the load increase output when an elevated slightly higher rotational speed than the minimum value R _B prevents the too high engine speed R by increase of the working machine 18 is prolonged This is because the output of increasing the load is turned off after confirming that the engine speed R has tended to increase.

On the other hand, if the mix control is being performed, the process proceeds from step 303 to step 307. After the load increase output is turned off, the process proceeds to the plowing depth control based on the depth sensor value (step 308). That is, since the engine speed R is performed immediately tilling depth control Once becomes equal to or greater than the minimum value R _B, it can return to quickly set tilling depth value working machine 18.

In step 203 of the load control shown in FIG. 4, when the engine speed R has not decreased to the lower limit value L _R , or when the rate of change D of the engine speed becomes the specified value D _R If it is smaller, that is, if there is no change in the engine speed R and it returns to the normal state, the load lowering output process is performed. The load lowering output process will be described with reference to FIGS. First, it is determined whether or not a predetermined time has elapsed after the load increase output is turned off or the load decrease output is turned off (step 401).

When a certain time has elapsed after the output is turned off, the lift arm sensor value θ _F stored in the memory when the output is turned off.
And the lift arm sensor value θ _S when the work implement 18 is located at the set plowing depth value is calculated (step 40).
2), lift arm sensor value θ corresponding to the set till depth position
By increasing the _S by 1/2 of the difference X and the correction lift arm sensor value theta _X (step 403). Subsequently, a difference X ₂ between the lift arm sensor value θ _F when the output is turned off and the corrected lift arm sensor value θ _X is calculated, and this difference X ₂ is set as one descent amount (step 404).

Then, the current lift arm sensor value θ_N
Is the corrected lift arm sensor value θ _XNegative until matches
The load lowering output is turned on (step 405 → 406). negative
The work implement 18 descends when the load lowering output is turned on, and the current lift
Arm sensor value θ_NIs the corrected lift arm sensor value θ_X
If it matches, go from step 405 to step 407
move on. Since the load lowering output is on, the load lowering output
(Steps 407 → 408) and lift at this time
The arm sensor value is stored in the memory (step 40).
9) The first load lowering output processing ends.

When a predetermined time has elapsed after the load lowering output has been turned off and the process returns to step 402 to perform the second load lowering output process, the lift arm sensor newly stored in the previous step 409 is used. value theta _F, the difference X between the lift arm sensor value theta _S corresponding to the set tilling depth position is half the previous value, to calculate a new correction lift arm sensor value theta _X on the basis of the difference X (step 403).
Similarly to the previous time, the difference X ₂ between the lift arm sensor value θ _F when the output is turned off and the corrected lift arm sensor value θ _X is calculated and set as the current descending amount (step 40).
4).

Then, the current lift arm sensor value θ _N
Is the load down the output on until matching new correction lift arm sensor value theta _X (step 405 → 406).
When the current lift arm sensor value θ _N matches the new corrected lift arm sensor value θ _X , the process proceeds from step 405 to step 407 again, and the load lowering output is turned off (step 408). The data is stored in the memory (step 409), and the second load lowering output process ends.

Although not shown, when the difference X is smaller than a predetermined value in step 402, that is, when the work implement 18 has sufficiently approached the set plowing depth, in step 404, X ₂ = X, the descending amount is set, and the descending amount is directly decreased until the current lift arm sensor value θ _N reaches the lift arm sensor value θ _S corresponding to the set plowing depth position, thereby terminating the final load lowering output process.

As described above, when lowering the work machine 18 after raising the work machine 18 by the load control, the first step corresponds to the work machine position when the load increase output is off and the set till depth value. Half of the difference from the work machine position, that is, the work machine 18
Is lowered by の of the rising amount of. Next, in the second step after the elapse of a predetermined time, the work is lowered by half the difference from the lowered position to the position of the work implement corresponding to the set till depth value, that is, the remaining half from the first step.

As described above, the work machine 18 descends stepwise by half of the difference from the set till depth value, and the descending amount for each step decreases as the set plow value approaches. In addition, there is no possibility that the working machine 18 will suddenly touch the ground and the load will increase rapidly, and the working machine can be returned to the original plowing state in the shortest time.

When the work implement 18 returns to the set plowing position, if the engine speed R continues to decrease, it is considered that the load is still large, and then the load increase output is turned on again. Work machine 18 is raised.

Further, when raising the working machine 18 by the load control, although the working machine 18 in Saiage position 8 has emerged from the field plane, the engine speed R is increased from the lowest value R _B Since the load increase output is turned off at the time, the work implement 18 may actually be in contact with the field scene at the highest position.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0035]

As described above, according to the present invention, in a tractor in which the working machine can be moved up and down by the plowing depth control and the load control, when the working machine is lowered after the working machine is lifted by the load control. Since the work machine is lowered step by step and the amount of descent in each step is gradually reduced, there is no danger that the work machine will suddenly touch the ground and the load will increase rapidly. Can be returned to the original plowing state.

Thus, the work machine can be quickly brought into contact with the ground, the load fluctuation after the grounding can be reduced, and work can be performed with good leveling.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention.

FIG. 1 is a side view of a tractor.

FIG. 2 is a block diagram of a tillage depth control and a load control system.

FIG. 3 is a flowchart in the case where the plowing depth control and the load control are performed in combination.

FIG. 4 is a flowchart of load control.

FIG. 5 is a flowchart of a load increase output off process.

FIG. 6 is a timing chart for a load increase output off process.

FIG. 7 is a flowchart of a load drop output process.

FIG. 8 is an explanatory diagram for explaining a lowering position of the work machine in the load lowering output process.

[Explanation of symbols]

 10 Tractor 16 Engine speed sensor 18 Work implement 27 Depth sensor 29 Controller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsuhiko Ikeda 1 Yatsukura, Tobe-cho, Iyo-gun, Ehime Prefecture Iseki Agricultural Machinery Co., Ltd. Department (72) Inventor Shingo Takagi 1 Togashi-cho, Tobe-cho, Iyo-gun, Ehime Prefecture Iseki Agricultural Machinery Co., Ltd.

Claims (1)

[Claims] 1. A tillage control in which a working machine for tilling is connected to a rear part of the body so as to be able to move up and down, and the working machine is moved up and down so that an actual tillage depth value detected by a depth sensor matches a set tillage value. A tractor having a load control for elevating and lowering the work implement such that the towing load of the work implement is determined from the engine speed and the engine speed is maintained within a predetermined range. When lowering the work machine after the ascending command is output, lower the work machine step by step by one step, and gradually reduce the amount of descent of one step as the set work depth approaches. Characteristic tractor load control device.