JP2527042B2 - Hydraulic lifting control device for ground work machine - Google Patents

Description

Description: [Industrial field of use] The present invention relates to a hydraulic lifting control device for lifting and lowering a ground work machine connected to a tractor or the like. In particular, the present invention relates to a depth control device configured such that a lower edge portion of a rear cover is brought into sliding contact with the ground to detect a change in tilling depth from its vertical movement.

[Prior art and its problems] Conventionally, the depth control is such that the lower edge of the rear cover that covers the rear of the tillage part is brought into sliding contact with the ground to pick up the unevenness, and the vertical movement change of the rear cover is electrically detected and detected. The system uses feedback to the hydraulic lifting mechanism. This detection is performed by a potentiometer installed on the upper part of the fixed side tillage cover, and the tilling depth is set by the tiller depth setting device installed near the cockpit so that the set value and the detected value always match. Lifting control is performed.

However, since this type of control device determines the ascending / descending speed of the hydraulic lifting device according to the difference between the set value and the detected value, in other words, the deviation, hunting is performed when the deviation is large and the fluctuation is severe. It has a drawback that it is easy to cause and control is not stable.

For example, if the soil in front of the rear cover is temporarily insufficient due to a local recess during cultivating work and the rear cover tends to sag to the front due to its own weight, the potentiometer detects that the working depth has decreased, and Therefore, the control section issues a command to deepen the plowing depth and the plowing section is lowered, but when the amount of soil in front of the rear cover increases again after overcoming the concave section,
Conversely, a command is issued to make the plowing depth shallow and the tilling section is raised. This has caused hunting if it is repeatedly performed during the tilling work.

[Means for Solving the Problems] The present invention is proposed in view of the above-mentioned problems, and an object thereof is to provide a hydraulic lifting control device for a ground work machine suitable for actual work with less hunting. .

Therefore, the present invention takes the following technical means. That is, when lowering the ground work implement 10 below the ground surface by the operation of the hydraulic operation lever 18 and performing cultivating work, a hydraulic lifting control mechanism including a proportional flow rate control valve 31 for raising and a proportional flow rate control valve 32 for lowering, Tillage depth setting device 20 that sets the working depth of the ground working machine 10, and plowing depth detector 26 that detects the working depth of the ground working equipment 10.
And a proportional flow rate control valve for ascending so that the ground work implement 10 is located at the working depth set by the working depth setting device 20.
31 and the proportional flow control valve 32 for descending control, when the cultivating depth change speed captured by the cultivating depth detector 26 is higher than the set cultivating depth changing speed, the control valves 31, 3
A hydraulic lifting control device for a ground work machine, characterized in that a control means (30) for restricting the inflow and outflow of hydraulic oil supplied and discharged to and from (2) is provided.

[Operation] When the ground working machine 10 is lowered below the ground surface and cultivated, the working depth is raised and lowered so as to match the set value set by the working depth setter 20. If the detected value detected by the tilling depth detector 26 is the same as the set value, the ascending / descending operation is not performed, and if there is a difference between the set value and the detected value, that is, if there is a deviation, the hydraulic lifting control mechanism Determines the ascending / descending speed of.
When the changing speed of the working depth, which is detected as a change in the detection value of the working depth detector 26, is higher than the set speed, the proportional flow rate control valve 3 for raising or lowering the hydraulic lifting control mechanism is used.
Output correction is performed so that the supply / discharge amount of hydraulic oil for 1,32 is less than the set amount. Therefore, the vertical movement of the rear cover is significantly suppressed, and there is little risk of hunting.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

First, the configuration will be described. 1 is a tractor equipped with an engine 2 at the front of the machine body, the rotational power of the engine 2 is appropriately reduced by a transmission in a mission case 3 behind the engine 2, and the power is transmitted to the front wheels 4, 4 and It is transmitted to the rear wheels 5, 5. A hydraulic cylinder case 6 is mounted on the upper rear part of the transmission case 3 in the rear part of the machine body, and lift arms 8, 8 are rotatably pivoted on both left and right sides of the case 6. Reference numeral 10 is a rotary tiller, which is movably connected to the tractor 1 via a three-point link mechanism including a top link 11, lower links 12, 12.

The rotary tiller 10 comprises a tiller 14, a main cover 15 that covers the tiller 14, a rear cover 16 that is pivotally attached to the rear end of the main cover 15, and the lower edge of the rear cover 16 is on the ground. Perform plowing work while making sliding contact. A working depth detector 26, which will be described later, is attached to the upper rear portion of the main cover 15.

FIG. 2 is a block diagram of a control device for hydraulically controlling the rotary tiller 10, and the detailed structure thereof will be described based on this block diagram.

Ground height setting device 19 mounted on the rotation base of the hydraulic operation lever 18 of the tractor 1, plowing depth setting device 20 for setting the working depth of the rotary tiller 10, and mounting on the rotation base of the one-side lift arm 8. Height detector 25, rotary tiller
The plowing depth detector 26, which is attached to the rear end portion of the main cover 15 of 10 and detects the plowing depth of the rotary tiller 10 by detecting the turning angle of the rear cover 16, includes an A / D converter 27, respectively. Is connected to the control unit 30 composed of a CPU via this control unit 30.
An output proportional flow control valve 31 for rising and a proportional flow control valve 32 for falling which constitute a hydraulic lift control device are connected to the output side of.

These proportional flow rate control valves 31, 32 are respectively the control valves 31,
The area of the pressure oil flow opening provided on the spool changes in proportion to the value of the current flowing through the 32 solenoids.
Rotation of the lift arm 8 so that the height of the entire rotary tiller, which is the ground work machine 10, is moved up and down to the set value set by the ground height setting device 19 attached to the rotation base of the hydraulic operation lever 18. The controller 30 outputs a current proportional to the magnitude of the detection value of the ground height detector 25 attached to the base, that is, the deviation, and the lift arm 8 makes a large rotation to descend the ground from the upper limit position. Go up and down to the following. When the raising / lowering position is at the excavation position where the tilling part 14 is below the ground, the rear cover is set to the setting value of the working depth setting device 20 for setting the working depth of the ground working machine 10, which is a main part of the present invention. The control unit 30 outputs a current proportional to the detected value of the tilling depth detector 26 for detecting the tilling depth of the ground working machine 10 as the swing angle of 16, ie, the deviation, and the lift arm 8 rotates slightly. Tillage part 14
Is used for energizing the excavation position when the position is below the ground to energize the proportional flow control valves 31, 32 for raising or lowering each of the hydraulic lifting control mechanism with a pulse current having a pulse width proportional to the current value. I am configuring.

Further, reference numeral 35 is a switch for forcibly raising and lowering which is directly connected to the control unit 30, and by turning the switch 35 ON and OFF, the rotary tiller 10 connected to the tractor 1 is forcibly moved up and down. Can be made.

Next, the operation of this embodiment will be described based on the flow chart shown in FIG. The procedure shown in this control flow is
The control program is stored in the control unit 30.

When the tiller 14 of the rotary tiller, which is the ground working machine 10, is at the excavation position below the ground and the depth control is started, the settings are made by setting tools such as the tiller depth setting device 20 and the ground height setting device 19. The value and the detection value by the detector such as the working depth detector 26 and the ground height detector 25 are read into the control unit 30 (step). For example, when the rear cover 16 moves upward in the direction in which the working depth becomes deep, the working depth detector 26 captures the change and at the same time, the change speed is calculated (step). When the tilling depth becomes gradually deeper, the controller 30 issues a rising command to the lifting proportional flow rate control valve 31 in order to lift the rotary tiller 10, but whether the rear cover 16 moves more than the posture change of the rear cover 16 due to this lifting. Is determined. That is, the changing speed of the rear cover 16 with respect to the automatic output is compared (step).
If the change speed is as set, the correction amount is set to "0" (step), and when the plowing depth change speed exceeds the setting, the difference between the set change speed and the actual change speed is obtained and calculated. The correction amount is set from the result (step). For example, when the bottom edge of the rear cover 16 tries to enter the recess when the plowing depth is deep, the rear cover 16 attempts to move to the front side. In this case, the lift arm 8,
By the upward movement of 8, the rear cover 16 shifts to the front side, and due to the newly appearing recess, the front side of the rear cover 16 temporarily lacks the amount of soil, so that the rear cover 16 tries to shift further to the front side. In such a case, the change rate is detected by the working depth detector 26, and the control unit 30
Since the ascending output which is suppressed from the normal case is output from the normal case, the ascending / descending speed of the rotary tiller 10 is controlled by the ascending output that is corrected before the rear cover 16 falls into the recessed portion. It can solve the conventional problems of sensitively detecting changes in the working depth and creating the cause of hunting.

Then, the direction in which the lift arms 8 and 8 are moved and the magnitude of the corrected output are determined from the difference between the set value and the detected depth value (step), and the lift arms 8 and 8 are determined.
Is moved up and down.

Note that FIG. 4 shows the relationship between the deviation and the flow rate of hydraulic oil. In this figure, the horizontal axis shows the difference between the set cultivation depth and the detected cultivation depth, and the vertical axis shows the flow rate. As is clear from the figure, the relationship between the two is set to a linear function characteristic. When setting the relationship between the two, a quadratic function or a function control in which the amount of increase is larger than that is possible, but since the undulations in the field are repeatedly formed with concavo-convex portions, changes in plowing depth also occur. It constantly changes such as becoming shallower or deeper, and if the working machine is moved at a high speed in response to such a change, it becomes easy to overshoot the target. From this point of view, the linear function control is more stable and the finish after working is also better.

The control program shown in FIG. 5 relates to an improvement of the depth control device described above. That is, the upper limit of the flow rate characteristic curve described in FIG. 4 is set.

There are many work machines attached to a tractor, and their weights are also different, and the maximum flow rate required to raise and lower them is different depending on the work machines. In a system that simply controls the flow rate based on the difference between the target value and the detected value, unless the maximum flow rate of the hydraulic oil that flows in and out of the control valve is set, the speed will be too high depending on the work machine and the control will be stable. A problem such as lack of property occurs. In particular, in depth control using a rotary tiller, there was a problem that the stability of the plowing depth varied greatly due to excessive fluctuations in the plowing depth.

This improved device defines a maximum set flow rate smaller than the maximum capacity of the control valve only when using a rotary tiller,
No matter how large the deviation becomes, the flow rate to be introduced into the hydraulic cylinder is controlled at a predetermined maximum set flow rate. FIG. 5 shows the flowchart thereof. In this way, in the rotary tiller, the maximum flow rate is controlled during the depth work, so even if a large control valve with a margin is installed, hunting does not occur due to over-control, and the finish of the ground surface after tilling work is done. Has a characteristic of being excellent.

[Advantage of the Invention] The present invention is an operation in which the control valves 31, 32 are supplied / discharged when the tilling depth change speed captured by the tilling depth detector 26 as described above is higher than the set tilling depth change speed. Since the control means 30 for restricting the inflow and outflow of oil is provided, even if the rear cover 16 picks up local unevenness and tries to react sensitively, the movement cannot operate at a speed higher than the set speed. As a result, the cultivated soil surface in the field is not wavy, and the cultivated traces are smoothly finished to improve the working accuracy.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is an overall side view, FIG. 2 is a block diagram, FIG. 3 is a flow chart, FIG. 4 is a flow rate characteristic chart, and FIG. 5 is a flow chart. , FIG. 6 is a diagram showing flow rate characteristics. Explanation of code 1 …… Tractor 2 …… Engine 3 …… Mission case 10 …… Ground work machine 18 …… Hydraulic control lever 19 …… Ground height setter 20 …… Plumage depth setter 25 …… Ground height detection Device 26 …… Plowing depth detector 30 …… Control means (control section) 31 …… Rise proportional flow control valve 32 …… Drop proportional flow control valve

Claims (1)

(57) [Claims] 1. A hydraulic lifting control provided with a proportional flow rate control valve 31 for raising and a proportional flow rate control valve 32 for lowering when the ground work implement 10 is lowered below the ground surface by the operation of the hydraulic operation lever 18 and cultivated. Mechanism, tillage depth setting device 20 for setting the tilling depth amount of the ground working machine 10, and tilling depth detector for detecting the tilling depth amount of the ground working machine 10
26, which is controlled up and down by the proportional flow rate control valve 31 for rising and the proportional flow rate control valve 32 for descending so that the ground working machine 10 is located at the working depth set by the tilling depth setting device 20, When the tilling depth change speed captured by the tilling depth detector 26 is higher than the set tilling depth change speed, the control valve 3
Control means 30 for restricting the inflow and outflow of hydraulic oil supplied to and discharged from 1, 32
A hydraulic lifting control device for a ground work machine characterized by being provided with.