JP3700292B2 - Tractor load control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a load control device for a tractor, and more particularly to a load control device for a tractor configured to raise and lower a work implement when the engine speed varies.
[0002]
[Prior art and problems to be solved by the invention]
A tilling load control that raises and lowers the work implement so that the actual working depth value detected by the depth sensor matches the set working depth value, and the working equipment traction load There is known a tractor that includes a load control for determining the engine speed from the engine speed and raising and lowering the work implement so that the engine speed is maintained within a predetermined range.
[0003]
After the work implement rises due to load control, when the engine speed returns to the normal state and the work implement is lowered, if the work implement is suddenly lowered and grounded, the load increases and the engine revolution decreases. Then, the work machine will rise again. In such a case, since the hunting occurs by repeatedly raising and lowering the work machine, a large undulation occurs in the field scene.
[0004]
In order to prevent this, a load control apparatus is known in which a certain height is set as one step and the work implement is lowered step by step step by step. However, when the set plowing depth value is deep, it is necessary to perform a descent operation of several steps to a dozen steps until the work implement reaches the set plowing depth value, and it takes time to return to the original plowing depth position. On the other hand, if the set height of one step is increased too much in order to quickly return the work implement to the set working depth value, when the set working depth value is shallow, the work implement simply exceeds the set working depth value by one step. In this case, the load suddenly increases and the work machine rises, causing hunting.
[0005]
Therefore, in a tractor equipped with plowing depth control and load control, when the work implement is lifted by load control and then lowered again, the work implement is promptly grounded and the load fluctuation after grounding is reduced, thereby leveling the ground. The technical problem which should be solved in order to perform work with good property arises, and this invention aims at solving this problem.
[0006]
[Means for Solving the Problems]
The present invention has been proposed in order to achieve the above object, and a tilling work machine is connected to the rear part of the machine body so as to be movable up and down, and the actual tilling depth value detected by the depth sensor is matched with the set tilling depth value. Plowing control for raising and lowering the work implement, and load control for determining the traction 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. In the tractor
When lowering the work implement after the load control raise command is output by load control, the work implement is lowered step by step step by step, and the first step is a certain time after the load increase output is turned off. Then, the load is lowered by half of the difference between the work implement position when the load increase output is off and the work implement position corresponding to the set tilling depth value, and after the second step , a new time is stored after a certain time has passed since the descent output is turned off. A load control device for a tractor that lowers the working position by a half of the difference between the working position and the working position corresponding to the set working depth value is provided.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a tractor 10, in which an engine 11 is mounted on the front portion of the tractor 10, and an electronic governor 12 is mounted on a side portion of the engine 11. The power of the engine 11 is decelerated by a transmission provided in the mission case 13 and transmitted to the front and rear wheels 14a, 14b or the rear wheel 14b and also to the PTO shaft 15. The engine speed is detected by an engine speed sensor 16.
[0008]
On the other hand, a working machine 18 for tillage is connected to the rear part of the tractor 10 via a link mechanism 17. This link mechanism 17 is a three-point link system comprising a top link 19 and left and right lower links 20, and the tip of the left and right lift arms 21 and the left and right lower links 20 are respectively connected by lift rods 22.
[0009]
Then, when the lift arm 21 is rotated by the operation of the lift cylinder 23 provided at the upper part of the mission case 13, the lower link 20 moves up and down to raise and lower the work implement 18. The rotation angle of the lift arm 21 is detected by a lift arm sensor 24. Further, a rear cover 26 is rotatably attached to the rear end of the main cover 25 of the work machine 18, and a rotation angle of the rear cover 26 is detected by a depth sensor 27.
[0010]
Here, a controller 29 is provided in the vicinity of the driver's seat 28, and a position lever 30, a working depth setting dial 31, a load control mode switch 32, and the like are provided in the controller 29. A vehicle speed sensor 33 is provided below the driver seat 28 . Further, a work implement raising / lowering switch 35 is provided in the vicinity of the steering wheel 34, and a steering angle sensor 37 is attached to the steering shaft 36.
[0011]
FIG. 2 is a block diagram of a tractor plowing depth control and load control system. Setting signals such as the position lever 30, plowing depth setting dial 31 and load control mode switch 32 described above are input to the controller 29. In addition, 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 the shift lever.
[0012]
The controller 29 calculates the actual tilling depth value from the rotation angle of the rear cover 26 detected by the depth sensor 27, and works so that the actual tilling value matches the set tilling depth value input by the tilling depth setting dial 31. The plowing depth control of the machine 18 is performed. If so, a control signal is output to the solenoid 41 for raising or lowering the solenoid proportional valve in order to raise and lower the work machine 18 by expanding and contracting the lift cylinder 23.
[0013]
On the other hand, the control of the electronic governor 12 outputs a control signal from the controller 29 to the rack actuator 43 in accordance with the detection value of the throttle position sensor 38, and adjusts 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 inform the operator that the load control is being executed.
[0014]
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 within a predetermined time. A change rate D of the engine speed is calculated.
[0015]
The lower limit value L _R of the engine speed and the specified value D _{R of the} rate of change of the engine speed corresponding to the set tilling value are determined in advance, and the engine speed R gradually decreases due to the work load and the lower limit value is reached. when it becomes less than 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 ascending command to the ascending solenoid 41 to raise the work implement 18 and prevent engine stall.
[0016]
When the working machine 18 is raised and the work load is reduced, the lowered engine speed R is raised and returned to a predetermined value, or the change rate D of the engine speed is reduced. Outputs a work implement lowering command from the controller 29 to the descending solenoid 42 to lower the work implement 18.
[0017]
FIG. 3 shows a flowchart when the plowing depth control and the load control are performed in combination. When the plowing depth control is “ON”, the process proceeds from step 102 to step 103, and when the load control is not “ON”, Plowing depth control is performed based on the detection value of the depth sensor 27 (step 103 → 105). When load control is “ON”, mixed control of plowing depth control and load control is performed (step 103 → 106). .
[0018]
On the other hand, when the tilling depth control is not “ON”, the process proceeds from Step 102 to Step 104. When the load control is “ON”, the load control is performed based on the detection value of the engine speed sensor 16. If the load control is not “ON”, the position control by the position lever 30 is performed (step 104 → 108).
[0019]
FIG. 4 shows a flow chart of the load control in the mix control in step 106 and the load control in step 107. The engine speed change rate D is calculated from the engine speed R read in step 101. However, if a work implement increase command by load control is not output, that is, if normal operation is continued and the load increase output is OFF, the process proceeds from step 202 to step 203.
[0020]
As described above, when the engine speed R by workload is below the lower limit L _R, or when the change rate D of the engine rotational speed is equal to or greater than the specified value D _R, ascending from the controller 29 A work implement raising command is output to the solenoid 41, that is, the load raising output is turned on (step 203 → 204).
[0021]
Here, if the load increase output is ON in step 202, the load increase output OFF process is performed next. 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. Becomes a load increase output on the engine speed R is less than the lower limit L _R by increasing the work load, but working machine load increases is reduced, yet the engine rotational Immediately after the load increase output on The number R continues to fall. 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).
[0022]
If you are running load control only proceeds from step 303 to step 304, in the load-up output off when the engine speed R is increased by the rotation number alpha (approximately 50-100 rpm) than the minimum value R _B ( Step 304 → 305), 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 load increase output is turned off after confirming that the engine speed R has been increasing.
[0023]
On the other hand, when the mix control is performed, the process proceeds from step 303 to step 307, and after the load increase output is turned off, the plowing depth control based on the depth sensor value is performed (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.
[0024]
And Thus, in step 203 the load control shown in FIG. 4, when the engine speed R is not decreased to the lower limit value L _R, or when the change rate D of the engine speed is less than the specified value D _R That is, when the engine speed R is not changed and the normal state is restored, the load lowering output process is performed. The load lowering output process will be described with reference to FIGS. First, it is determined whether a fixed time has elapsed after the load raising output is turned off or the load lowering output is turned off (step 401).
[0025]
When a certain time has elapsed after the output is turned off, a difference X between 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. Then, the lift arm sensor value θ _S corresponding to the set plowing depth position is increased by ½ of the difference X to obtain a corrected lift arm sensor value θ _X (step 403). Subsequently, a difference X ₂ between the lift arm sensor value θ _F when the output is off and the corrected lift arm sensor value θ _X is calculated, and this difference X ₂ is set as a single descent amount (step 404).
[0026]
Then, the load lowering output is turned on until the current lift arm sensor value θ _N matches the corrected lift arm sensor value θ _X (step 405 → 406). When the load lowering output is turned on, the work implement 18 is lowered, and when the current lift arm sensor value θ _N coincides with the corrected lift arm sensor value θ _X , the process proceeds from step 405 to step 407. Since the load lowering output is on, the load lowering output is temporarily turned off (step 407 → 408), the lift arm sensor value at this time is stored in the memory (step 409), and the first load lowering output process is completed.
[0027]
Thus, when the routine reaches step 402 again to perform the second load lowering output process after a lapse of a certain time from the load lowering output OFF, the lift arm sensor value θ _F newly stored in the previous step 409 is stored. Then, the difference X from the lift arm sensor value θ _S corresponding to the set tilling position is half of the previous value, and a new corrected lift arm sensor value θ _X is calculated based on 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 off and the corrected lift arm sensor value θ _X is calculated and set as the current descending amount (step 404).
[0028]
Then, the load lowering output is turned on until the current lift arm sensor value θ _N matches the new corrected lift arm sensor value θ _X (step 405 → 406). When the current lift arm sensor value θ _N coincides with the new corrected lift arm sensor value θ _X , the process proceeds from step 405 to step 407 again to turn off the load lowering output (step 408). This is stored in the memory (step 409), and the second load lowering output process is completed.
[0029]
Although not shown in the drawing, when the difference X becomes smaller than a certain value in step 402, that is, when the work implement 18 has sufficiently approached the set plowing depth position, in step 404, X ₂ = X. The descending amount is set, and the current lift arm sensor value θ _N is directly lowered until the current lift arm sensor value θ _N reaches the lift arm sensor value θ _S corresponding to the set tilling position, and the final load lowering output process is terminated.
[0030]
Thus, when lowering the work implement 18 after raising the work implement 18 by load control, first, the first step is the work implement position when the load increase output is off and the work implement position corresponding to the set working depth value. Is lowered by half of the difference between the two, that is, ½ of the rising amount of the working machine 18. Next, the second step after the elapse of a fixed time is lowered by half of the difference from the lowered position to the work implement position corresponding to the set tilling depth value, that is, the remaining half from the first step.
[0031]
Thus, the work implement 18 descends stepwise by half of the difference from the set plowing depth value, and the amount of descent at each step decreases as it approaches the set plowing depth value. There is no fear that 18 will be grounded suddenly and the load will increase rapidly, and the work implement can be returned to the original plowing state in the shortest time.
[0032]
When the working machine 18 returns to the set plowing position, if the engine speed R continues to decrease, the load is considered to be still large. In this case, the load raising output is turned on again and the working machine is turned on. Raise 18
[0033]
Further, when increasing the working machine 18 by the load control, although the working machine 18 in Saiage 8 position has emerged from the field plane, the load when the engine speed R is increased from the lowest value R _B Since the lift output is turned off, the work machine 18 may actually be in contact with the farm scene at the highest position.
[0034]
It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.
[0035]
【The invention's effect】
As described above, in the present invention, in the tractor that allows the work implement to be moved up and down by plowing depth control and load control, when the work implement descends after the work implement ascent command is output by load control, The work implement is lowered step by step , and in the first step , a fixed time elapses after the load rise output is turned off , and the work implement position when the load rise output is turned off and the work implement position corresponding to the set working depth value. Decrease by 1/2 of the difference between the first and second steps, and after a certain period of time has elapsed since turning off the load lowering output , decrease by a half of the difference from the newly stored work position to the work position corresponding to the set working depth value. Therefore, as the set working depth value is approached, the amount of descent at each step decreases, so there is no risk that the work equipment will suddenly touch the ground and the load will increase rapidly, and the work equipment will be returned to its original position in the shortest possible time. Can be returned to the plowing condition .
[0036]
Thus, it is possible to perform work with good leveling by grounding the working machine promptly and reducing the load fluctuation after the grounding.
[Brief description of the drawings]
The figure shows an embodiment of the present invention.
FIG. 1 is a side view of a tractor.
FIG. 2 is a block diagram of a tilling depth control and load control system.
FIG. 3 is a flowchart in a case where plowing depth control and load control are used 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 regarding load increase output off processing;
FIG. 7 is a flowchart for a load lowering output process.
FIG. 8 is an explanatory diagram for explaining a lowered position of the work machine in the load lowering output process.
[Explanation of symbols]
10 Tractor 16 Engine Speed Sensor 18 Work Machine 27 Depth Sensor 29 Controller

Claims (1)

A tilling load control that raises and lowers the work implement so that the actual working depth value detected by the depth sensor matches the set working depth value, and the working equipment traction load In a tractor having a load control for moving the work implement up and down so that the engine speed is maintained within a predetermined range.
When lowering the work implement after the load control raise command is output by load control, the work implement is lowered step by step step by step, and the first step is a certain time after the load increase output is turned off. Then, the load is lowered by half of the difference between the work implement position when the load increase output is off and the work implement position corresponding to the set tilling depth value, and after the second step , a new time is stored after a certain time has passed since the descent output is turned off. A load control device for a tractor, wherein the load control device lowers by a half of a difference between a work position and a work position corresponding to a set working depth value.

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