JPH0387103A - Hydraulic controller for lifting and lowering of ground working machine - Google Patents

Abstract

PURPOSE:To reduce hunting by limiting outflow or inflow of a hydraulic fluid fed and discharged from control valves when the rate of plowing depth change is larger than the set rate of change. CONSTITUTION:When the rate of plowing depth change caught by a plowing depth sensor 26 is higher than the set rate of plowing depth change, a controlling means 30 for limiting the outflow or inflow of a hydraulic fluid fed or discharged from a proportional flow control valve 31 for lifting and a proportional flow control valve 32 for lowering is provided. Even if a rear cover tends to react by picking local unevenness, the movement thereof is incapable of operating over the set rate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] 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 to allow the lower edge of the rear cover to slide into contact with the ground and detect changes in plowing depth from the vertical movement of the lower edge of the rear cover.

[Prior art and its problems] Conventionally, depth control involves sliding the lower edge of the rear cover that covers the rear of the tilling area against the ground to pick up changes in its unevenness, electrically detecting changes in the vertical movement of the rear cover, and detecting it. It uses a type of feedback to the hydraulic lifting mechanism. This detection is performed by a potentiometer installed on the top of the tilling cover on the fixed side, and the tilling depth is determined by a tilling depth setting device installed near the cockpit, so that the set value and detected value always match. Elevation control is performed.

However, this rare control device determines the lifting speed of the hydraulic lifting device according to the difference between the setting device and the detected value, or in other words, the deviation, so if the deviation is large and the fluctuation is severe, hunting is not performed. The problem was that it was easy to raise the soil and the control was unstable. For example, during tilling work, if there was a temporary shortage of soil in front of the rear cover due to a local depression, and the rear cover tended to gather toward the front under its own weight, The potentiometer detects that the plowing depth has become shallow, and therefore the control unit issues a command to increase the plowing depth, but when the amount of soil in front of the rear cover increases again after going over the depression, the opposite occurs. A command was issued to reduce the depth of plowing, and if this was done repeatedly during plowing, it would cause hunting.

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

For this reason, the present invention has taken the following technical measures.

That is, a curved tail lift control mechanism equipped with 3 ascending proportional flow control valves and a descending proportional flow control valve 32, and 0 ground work mechanisms.
It consists of a setting device 20 that sets the plowing depth amount of the ground work device 10, and a detector 26 that detects the plowing depth amount of the ground work device 10. 1
When the plowing depth change speed detected by the plowing explorer device 26 is greater than the set plowing depth change speed, when the plowing depth change speed is higher than the set plowing depth change speed, the The oil) E elevation control device for ground-based work equipment is characterized in that it is provided with a control means 30 for restricting the inflow and outflow of hydraulic oil.

[Function] Normally, the lifting speed of the hydraulic lifting device is determined according to the difference between the setting A1# and the test +l' + 4ft, that is, the deviation, but the plowing depth change speed captured by the plowing depth detection value is set. When the speed is higher than the set speed, output correction is performed so that the amount of hydraulic oil supplied to the control valve is less than the set amount. Therefore, vertical movement of the rear cover is significantly suppressed, and there is little risk of hunting.

[Example code] The present invention will be described in detail below with reference to the drawings.

First, to explain the configuration, 1 is a tractor with an engine 2 mounted on the front of the fuselage, and the rolling force of the 1F1 of the engine 2 is appropriately decelerated by a coupling device in the mission case 3 behind it, and the power is transferred to the front wheels 4. .4 and the rear wheels 5.5. A hydraulic cylinder case 6 is mounted on the rear upper part of the mission case 3 at the rear of the fuselage, and a rift 1 to an arm 8.8 are pivotally connected to both left and right sides of the case 6 so as to be movable together. Reference numeral 10 denotes a rotary tiller, which includes a top link 11 and a lower link 1.
2. It is connected to 1 to Rakuta↓ via a three-point link mechanism consisting of 12 so that it can be raised and lowered.

The rotary tilling device 10 includes a tilling section 14, a main cover 15 on which the tilling section 14 is placed. It consists of a rear cover 16 etc. which is pivotally attached to the rear end of the main cover 15 so that it can move freely.
Perform deep plowing work without letting the lower edge of 6 slide into contact with the ground.

A plowing depth detector 26, which will be described later, is attached to the rear upper part of the main cover 15.

FIG. 2 is a block diagram of a control device that hydraulically controls this rotary tiller 10, and its detailed structure will be explained based on this block diagram.

Ground height setting device 19 attached to the cooperating base of the hydraulic control lever 18 of the tractor. A tillage depth setting device 20 for setting the tillage depth of the rotary tillage device 10, a ground height detector 25 attached to the rotation base of the negative side lift arm 8, and a rear end of the main cover 15 of the rotary tillage device 10. A plowing depth detector 26 is attached and detects the plowing depth of the rotary tiller IO by detecting the rotation angle of the rear cover 16.
A control unit 3 consisting of a CPU via an A/D converter 27, respectively.
0, and an ascending proportional landscape control valve 31 and a descending proportional flow rate control valve 32 are connected to the output side of the control unit 30, which constitute a hydraulic elevation control device.

These proportional flow control valves 3'', 32 are the respective control valves 3
The area of the pressure oil flow opening provided in the spool changes in proportion to the current value applied to the solenoid 32, and the current proportional to the magnitude of the detected value, that is, the deviation from the set value, changes in the control unit 30. The structure is such that a pulse current is outputted from the solenoid and has a pulse width proportional to the current value and is applied to each solenoid.

Further, reference numeral 35 is a forced raising/lowering switch directly connected to the control unit 30, and when this switch 35 is turned on,
By turning off the rotary tiller 10, the rotary tiller 10 connected to the tractor 1 can be elastically moved up and down.

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

First, when depth control is started, set values by setting devices such as the plowing depth setting device 20 and ground height setting device 19, and detected values by detectors such as the plowing depth detector 26 and the ground height detector 25, etc. is read into the control unit 30 (of step). for example,
When the rear cover 16 moves upward in the direction of increasing the plowing depth, the plowing depth detector 26 detects the change, and at the same time, the rate of change is calculated (step (2)). As the plowing depth gradually increases, a lifting command is issued from the control unit 30 to the lifting proportional flow rate control valve 31 in order to pull up the rotary tilling device 1W10.
It is determined whether or not 6 moves. That is, the rate of change of the rear cover 16 with respect to the automatic output is compared (step 2). If the rate of change is as set, the correction amount is set to "O" (step ■).
When the plowing depth change speed exceeds the setting twice, the difference between the set change speed and the actual change speed is calculated, and a correction amount is set from the calculation result (step ■■). For example, when the plowing depth is increasing, when the lower edge of the rear cover 16 tries to enter the recess, the catcher cover 16 tends to move toward the front side. In this case, the rear cover bay 6 moves to the front side due to the upward movement of the lift arm 8.8, and the amount of soil on the front side of the rear cover 16 is temporarily insufficient due to the newly appeared concave portion. It tries to shift to the front side, but in such a case, the plowing depth detector 26
The rate of change is detected by the controller 30, and a rising output that is lower than that in the normal case is output from the controller 1.
The lifting speed of the rotary tiller 10 is controlled by the corrected 1L lifting force before the rotary tiller 6 falls into the recess,
This makes it possible to eliminate the conventional problem that the rear 8 cover 16 sensitively detects changes in plowing depth in localized recesses, causing hunting.

Then, the direction in which the lift arm 8.8 is moved and the magnitude of the corrected output are determined based on the difference between the plowing depth setting value and the plowing depth detection value (step ■■), and the lift l-arm 8.8
is raised and lowered.

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 plowing depth and the detected plowing 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.6 When setting the relationship between the two, it is also possible to use a quadratic function or a function control with a larger increment. Because the undulations of the field are continuously formed by repeating uneven parts, the plowing depth changes constantly, from shallower to deeper, and it is necessary to move the work equipment at high speed in response to such changes If so, it becomes easy to overshoot the target. From these points of view, linear function control is more stable and produces a better finish after work.

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

There are many working machines attached to tractors, and their weights also vary, and the maximum flow rate required to raise and lower them varies depending on the working machine. In a method that simply controls the flow rate according to the difference between the target value and the detected value, the maximum flow rate of hydraulic oil flowing into and out of the control valve must be set, or the speed of some work equipment may be too high, resulting in unstable control. Problems such as lack of sex will occur. In particular, depth control using a rotary tiller has the problem of large fluctuations in tillage depth due to overshooting, resulting in a loss of stability.

This improved device sets a maximum set flow rate that is smaller than the maximum capacity of the control valve only when using a rotary tiller, and no matter how large the deviation becomes, the flow rate flowing into the hydraulic cylinder is limited to the predetermined maximum set flow rate. This is how it was done. FIG. 5 shows the flowchart. In this way, in rotary tillage equipment, the maximum flow rate is limited during depth work, so even if a large control valve with plenty of room is installed, hunting due to overcontrol will not occur, and the finish of the ground surface after tillage work will be improved. It has the characteristics of good performance.

[Effects of the Invention] As described above, when the plowing depth change speed detected by the plowing depth detector 26 is greater than the set plowing depth change speed, the control valves 31 and 32 are supplied with and discharged from the control valves 31 and 32. Since the control means 30 is provided to restrict the inflow and outflow of oil, even if the rear cover 16 picks up local irregularities and tries to react sensitively, its movement cannot exceed the set speed, and this As a result, the surface of the plowed soil in the field will not be violently undulated, and the plowed soil will be finished smoothly, improving work accuracy.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is an overall side view, Fig. 2 is a block diagram, Fig. 3 is a flowchart, Fig. 4 is a diagram showing flow characteristics, and Fig. 5 is a flowchart. Charts 1 to 6 are diagrams showing the special names of ryūsha. Description of symbols Tractor engine mission case Ground height corrector Plowing depth setting device Ground height detector Plowing depth detector Control means (control unit) Proportional flow control valve for ascending Proportional flow control valve for descending

Claims (1)

[Claims] A hydraulic lift control mechanism equipped with an ascending proportional flow control valve 31 and a descending proportional flow control valve 32, a setting device 20 for setting the plowing depth of the ground working machine 10, and detecting the plowing depth of the ground working machine 10. and a detector 26 for setting the plowing depth setting device 20.
In the case where the ground working machine 10 is controlled to rise and fall so that it is positioned at the plowing depth set by A hydraulic lifting control device for a ground-based work machine, characterized in that a control means 30 is provided for restricting the inflow and outflow of hydraulic oil supplied to and discharged from control valves 31 and 32.