JPH0720404B2 - Hunting prevention device in the working depth control part of the ground work machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hunting prevention device in a working depth control unit of a ground work machine.

(B) Conventional technology Conventionally, a ground work machine such as a rotary tiller, which is connected to a tractor or the like via an elevating mechanism so as to move up and down, has a means for detecting the tilling depth of the tilling claw and the claw is grounded. It is equipped with a means for detecting the time from, and a calculation means for calculating the detection value of each detection means, and controls the lifting mechanism based on the calculation result, so that the working machine is located above the ground surface. From the start to the plowing work position, the work implement is suddenly lowered to improve work efficiency and the headland is squeezed. Once the work implement descends to the plowing work position, a slow descent operation suitable for plowing work. A descending speed control device for a ground working machine has been invented which enables two kinds of descending speed control of working machines (Japanese Patent Application No. 61-261017).

(C) Problems to be Solved by the Invention However, in the above device, hunting occurs immediately after descending to the plowing work position, and the work machine vibrates up and down, especially during shallow plowing work. Overshooting is likely to occur because the set plunging depth is reached without the descent speed being sufficiently slowed down.Therefore, the dead zone width of plowing depth control, which indicates the range in which the plowing depth detection value does not work effectively, is set larger than the overshoot amount. It is used or the work machine is used in a semi-fixed state.In such a state, the plowing work is not sufficiently controlled, so it is difficult to make the finished state of tilling work uniform, and waviness occurs on the surface. There was a defect that it caused the unevenness on the cultivator.

(D) Means for Solving the Problems In the present invention, a rotary tiller working machine connected to a tractor via a lifting mechanism so as to be lifted and lowered, and a working depth for detecting a working depth of a tilling claw of the rotary tiller working machine. The tilling depth detection value of the tilling depth detecting means is provided with a detecting means and a calculating means for comparing and calculating the tilling depth detected value of the tilling depth detecting means and the set value of the tilling depth and outputting the result to the lifting mechanism. It is configured to keep the working depth of the rotary working machine constant by controlling the operation of the lifting mechanism based on the above, and the calculating means includes the set value of the working depth and the working depth from the working depth detecting means. In the working depth control of the ground working machine in which the dead zone width indicating the range in which the detected value does not work effectively is provided, the elapsed time detecting means for detecting the elapsed time after the deep-growing claw touches the ground is provided, and the same elapsed time detecting means is provided. But,
A tilling depth control unit for a ground work machine, characterized in that the dead zone width is set wide until it is detected that a certain period of time has elapsed after the tilling claw touches the ground, and the dead zone width is set narrow after the certain period of time has elapsed. It is intended to provide a hunting prevention device in.

(E) Action / Effect According to the present invention, by setting the dead zone width of tilling depth control large until a predetermined time elapses after the lower end of the tilling claw touches down, hypersensitivity immediately after the descent operation of the working machine. The above-mentioned hunting is prevented by suppressing various control operations, and the dead zone width is narrowed after a lapse of a predetermined time to perform precise plowing depth control, so that plowing work results even during shallow plowing work. As a result, it is possible to obtain a flat plowing surface and a finishing machine with no unevenness.

(F) Embodiment An embodiment of the present invention will be described in detail with reference to the drawings.
Indicates an agricultural tractor, which is equipped with an engine (2) and a prime mover (4) having a hydraulic pump (3) directly connected to the engine (2) on the upper surface of the frame (1). A transmission case (6) is connected to the rear part of the clutch housing (5) connected rearward to drive the left and right rear wheels (7) stretched on the left and right sides of the case (6), and at the same time, the frame (1 ), The left and right front wheels (8) stretched on the left and right sides of the steering wheel (10) are steered by the steering wheel (10) provided upright on the driving section (9) to drive the tractor (A).

Further, on the rear surface of the mission case (6), a hitch (11) which can be tilted left and right is continuously provided, and a working machine (B) is connected through the hitch (11). ) Is the interlocking mechanism (1
It is configured to rotate through 4) and till the field scene with plowing claws (15) planted in large numbers on the same axis (13).

A rear cover (16) rotatable about an upper end of the upper cover (26) is provided behind the tiller claw (15), and the machine frame (12) is further provided. A tail wheel (18) is hung from the rear of the through a depth adjusting frame (17).

A hydraulically operated lifting mechanism (19) is arranged on the upper surface of the mission case (6), and the left and right lift arms (20) (21) extending rearward from the mechanism (19) are The arm (20) is rotated up and down around the same mechanism (19).
The tip of (21) is connected to the machine frame (12) of the rotary working machine (B) via the lift rod (22), and the working machine (b) is moved up and down by the operation of the mechanism (19). It is what makes me. The work machine (B) is raised by the hydraulic pressure from the hydraulic pump (3), while the work machine (B) is lowered by the weight of the work machine (B).

Further, a hydraulic cylinder (23) for rolling the rotary working machine (B) with respect to the tractor (A) is provided in the middle of the right lift rod.

The operation of these hydraulic actuators is controlled by the control device (C) configured as described below.

That is, the same tractor (A)
A pitching sensor (24) for detecting the front-back inclination of the hitch (24) is arranged on the left side of the driving section (9), and a rear side of the mission case (6) and a hitch (which is connected to the rear side so as to be tiltable left and right). A rolling sensor (25) for detecting the relative inclination between the tractor (A) and the rotary working machine (B) is stretched between the 11) and the upper cover (26) of the rotary working machine (B). The rotation angle of the rear cover (16) is
A rear cover sensor (28) is provided as a working depth detecting means for detecting the working depth of the tilling claw (15) by detecting it through the rod (27).

Further, a lift sensor for detecting the vertical rotation position of the working machine (B) by detecting the vertical rotation angle of the left lift arm (20) of the lift mechanism (19) and detecting the vertical rotation angle of the arm (20). (29)
And a reverse detection sensor (31) that outputs when the lever (30) is in the reverse position is provided at the base end of the speed change lever (30) on the left side of the operating section (9). I have set up.

The operation of the lifting mechanism (19) and the rolling hydraulic cylinder (23) is performed by the above sensors (24) (25).
It is controlled by the detection results of (28) (29) (31),
As a control device (C) for initializing this control and switching the control mode, a control box (32) is arranged on the upper surface of the right fender of the operating section (9).

The control box (32) internally has an elapsed time detecting means for detecting the passage of time, a microcomputer (33) as an arithmetic means for calculating the detection result from each detecting means and outputting the calculation result, and an input / output interface ( 33
-1) (33-2) and other peripheral devices are built in, and the mode switching dial (34), work machine vertical position setting dial (35), working depth setting dial ( 36), sensitivity setting switch for plowing depth control (37), lifting switch (38) for manually lifting the working machine (B),
A left / right tilt angle setting dial (39), a left / right tilt speed setting switch (40), and a left / right tilt reversing switch (41) are provided between the tractor (A) and the work implement (B).

Then, the output from each sensor (24) (25) (28) (29) (31) is sent to each dial and switch (34) (35) (36) (37) (38) by the microcomputer (33). (3
9) The electromagnetic hydraulic control valve (42) (43) for controlling the operation of the lifting mechanism (19) and the hydraulic cylinder (23) for rolling by processing by referring to the set positions of (40) (41). It is configured to output control to the solenoids (44) (45) (46) (47).

In particular, the lowering control of the lifting mechanism (19) by the rear cover sensor (28) controls the lowering of the working machine (B) from the upper position away from the ground surface to the plowing work position and maintains a constant plowing depth during work. There are two types of control to
First, referring to FIG. 6 and FIG. 7, the former will be output (48) from the microcomputer (33) to the working machine lowering solenoid (45) by operating the elevating switch (38) of the control box (32). Then, the descending side port of the electromagnetic hydraulic control valve (42) opens, and the working machine (B)
Makes a rapid descent (49).

This rapid descent (49) is controlled by the output (48), and the same signal (48) is sent to the ground of the working machine (B) by the signal from the lifting sensor (29) provided in the lifting mechanism (19). The duty ratio is controlled so as to decrease gradually as the height decreases, and therefore the duty ratio is controlled so that the descending speed gradually decreases as the work implement (B) approaches the ground surface from above. ing.

Then, the working machine (B) descends, the lower end (16-1) of the rear cover (16) contacts the ground surface and is pushed up, and the detection value (50) from the rear cover sensor (28) rises ( 50a), the ground contact is detected by this rising (50a), and the above-mentioned operation is performed for a predetermined time (t) (about 2 seconds in this embodiment) from the time of contact with the ground by using the timer function of the microcomputer (33). The duty ratio of the output (48) is continuously decreased, and after a lapse of a predetermined time (t), control for maintaining a constant working depth is performed.

In the case of the above deceleration, it can be adjusted by changing the duty ratio of the pulsed output (52).

Therefore, the grounding of the lower end of the tilling claw (15-1) is detected by the output from the rear cover sensor (28), and the electromagnetic output of the electromagnetic hydraulic control valve (42) is detected by the pulsed output (52) as the working machine descending speed deceleration means. By configuring the solenoid (45) to operate, it is possible to decelerate the descending speed of the working machine (B) from the grounding of the tiller claw lower end (15-1) until a predetermined time elapses. Therefore, it is possible to prevent the harmful effects caused by the biting of the tilling claw (15).

Next, the control for maintaining a constant working depth will be described with reference to FIG. 8. During the plowing work, the rear cover sensor (28) continuously outputs the detected value (50) of the working depth, If the value obtained by subtracting the detected value (50) from the set value (51) set with the plowing depth setting dial (36) is positive, that is, if the plowing depth is shallower than the set value, a duty ratio of approximately proportional to the subtracted value will be obtained. The pulse output (52 ') is output to the solenoid (45) to lower the working machine (B) at a lowering speed that is approximately proportional to the deviation from the set value (51).

Therefore, since the working depth of the working machine (B) is controlled by the proportional control in which the control amount is proportional to the deviation from the target value, the advanced working depth control is performed and the constant working depth can be maintained quickly. It has the effect of being performed stably.

Note that (54) indicates the dead zone width that is set by sandwiching the set value (51) so that the detected value of plowing depth does not work effectively. If the dead zone width (54) is narrowed, the plowing depth control becomes precise. However, the control operation is performed even for a slight change in the working depth, and the control becomes hypersensitive, and when the dead zone width (54) is narrow immediately after the descent operation of the working machine (B), during shallow plowing work. Since the descending speed of the working machine (B) is not sufficiently reduced, an overshoot occurs, and this overshoot easily causes hunting.

Therefore, in the present invention, as shown in FIG.
A wide dead band width (54a) is set to prevent the occurrence of hunting for a certain period of time (t ') after the touchdown at the ground (t'), that is, immediately after the descent operation of the work machine (B) that is prone to hunting. ′) After the possibility of hunting has decreased after setting, by setting a narrow dead zone width (54b), precise tillage depth control can be performed, so that even when the shallow tillage work is started, there is no hunting. It is possible to control the plowing depth.

As described above, in the present embodiment, the descent operation speed control of the working machine from the upper position to the plowing work position is gradually decelerated as the ground height of the working machine is reduced, so that the dashing at the time of grounding of the working machine is performed. And while preventing stalling, it is possible to shorten the time required for the work machine to descend to descent, and to proportionally control the descending speed to maintain a constant plowing depth during plowing work, and Prevents hunting even during dead zone width of tilling depth control for a certain period of time,
Moreover, there is an effect that a constant working depth is maintained quickly and precisely.

[Brief description of drawings]

FIG. 1 is an overall side view of a ground work machine having a hunting prevention device according to the present invention. FIG. 2 is a plan view (partially deleted). FIG. 3 is a plan view of the control box. FIG. 4 is a hydraulic circuit diagram. FIG. 5 is a block diagram of the control device. FIG. 6 is a graph showing the output characteristics of the rear cover sensor. FIG. 7 is a graph showing the relationship between the working machine descending speed from the upper position to the plowing work position and the output to the solenoid. FIG. 8 is a graph showing the relationship between the working machine descending speed for maintaining a constant plowing depth and the output to the solenoid. FIG. 9 is a graph showing a plowing depth control operation and a dead zone width immediately after the work implement descending operation. (A): Tractor (B): Working machine (15): Plowing claw (19): Lifting mechanism

Claims (1)

[Claims] 1. A rotary tiller (B) connected to a tractor (A) via a lifting mechanism (19) so as to be lifted and lowered,
The tilling depth detecting means for detecting the tilling depth of the tilling claw (15) of the rotary tiller (B) and the tilling depth detecting value of the tilling depth detecting means and the set value of the tilling depth are compared and calculated, and the result is calculated. Lifting mechanism (19)
And a calculation means for outputting to the cultivating depth detecting means for controlling the operation of the lifting mechanism (19) based on the detected value of the cultivating depth. At the same time, in the tilling depth control of the ground working machine in which the calculating means includes the set value of the tilling depth and the dead zone width indicating the range in which the tilling depth detection value from the tilling depth detecting means does not work effectively is set, Providing an elapsed time detecting means for detecting an elapsed time after the nail (15) is grounded, and the elapsed time detecting means has passed a certain time (t ') since the tilling nail (15) is grounded. A hunting prevention device in a tilling depth control unit of a ground work machine, wherein the dead zone width is set wide until the detection of "," and the dead zone width is set narrow after a lapse of a certain time (t ').