JPS62228202A - Rellef valve continuous operation preventing apparatus in automatic controller of agricultral working machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to the attitude and working position ( The present invention relates to a working machine automatic control device for automatically controlling the plowing depth (plowing depth, etc.) to a set value.

O Conventional technology This type of automatic agricultural machine control device (work machine posture control device 1 work machine plowing depth control device) controls the hydraulic cylinder that drives the lift arm for lifting and lowering the work machine and the supply of hydraulic oil to the hydraulic cylinder. A work equipment lifting hydraulic circuit including a solenoid valve for lifting and lowering the work equipment is provided, and the operation of the working equipment lifting hydraulic circuit is controlled based on input signals from a detector and a setting device. There are 177 known devices that are controlled by a device.

In the agricultural working machine automatic control device described above, the working machine lifting hydraulic circuit is provided with a relief valve.

In the above-mentioned prior art, there is a finite upper and lower dead zone for positioning the control operation, and a setting device is used to make the entire mechanical stroke of the hydraulic cylinder within the control range.

Precise positioning is required to set the detector, and if the setting is incorrect, the relief valve will operate continuously on one side of the stroke end of the hydraulic cylinder, causing problems such as continuous operation noise and rising oil temperature. There are drawbacks that arise.

In order to eliminate the above-mentioned drawbacks in the prior art, the present invention prevents continuous operation of the relief valve at the stroke end of the hydraulic cylinder even if an error occurs in the setting of the setting device or the detector. This is the purpose.

Means for Solving the Problem The present invention provides a control device for controlling the energization of a solenoid valve for lifting and lowering a work equipment in a hydraulic circuit for lifting and lowering a work equipment, and for detecting the presence or absence of a change in a detector output during an effective minute time. When the solenoid valve is energized and the data change stop detecting means (11) detects the stop of data change, the work equipment lifting solenoid valve (
4), the solenoid valve drive circuit (1)
3), drive circuit output stopping means (12) is provided.

0 action When a setting deviation occurs in the setting device (6) or the detector, the work equipment operates in accordance with the setting device signal, and the detection signal stops the solenoid valve energization in response to the setting device signal. In a state where the value cannot be reached (in other words, when the hydraulic cylinder reaches the end of its stroke, the difference from the setter signal is still greater than the value equivalent to the positioning dead zone), The controller (10) continues to output the solenoid valve activation signal, and the hydraulic cylinder (2) is at the low end, so the relief valve (3) operates, but the stroke end of the hydraulic cylinder (2), that is, the detection The data change stop detection means (11) detects a state in which the detected value of the device (6) does not change for a finite minute time, and the work is stopped via the drive circuit output stop means (12). ) automatically stops energizing.

Therefore, the supply of hydraulic oil to the hydraulic cylinder (2) is stopped.
Continuous operation of the relief valve (3) is also prevented.

O Embodiment In the embodiment shown in FIG. 3, the detector (6) is
Work equipment position detector (lift arm position sensor')
(6a), tillage depth detector (rear cover sensor) (6
b) is installed at a predetermined position on the aircraft body and used as a setting device (7).
A work machine-to-machine position setting device (7a) and a work machine plowing depth setting device (7b) are provided. The work machine to main machine position setting device (7a) sets the relative position of the work machine to the main machine, and the work machine plowing depth setting device (7b) sets the elevation position relative to the ground. Equipped with analog switch (14), A/D converter (15), microcomputer (16) and solenoid valve drive circuit (13) 0:5 L/
Attach the controller (10) to the appropriate location on the work machine or this machine. In Figure 3, (8) is
Controller operation switches such as a switch for raising and lowering the work machine and a manual/automatic changeover switch; and (9) are warning devices such as a buzzer and an indicator lamp.

The work equipment position detector (6a) detects the attitude of the work equipment (plowing work equipment) relative to the main machine (tractor), and the detection signal is an analog voltage signal, which is sent via the analog switch (14) in the controller (10). A/D converter (15)
The signal is converted into a digital signal and taken into the microcomputer (16). Signals from the rear cover sensor (6b) to the work machine plowing depth setting device (7b) follow the same process and are sent to the microcomputer (16).
).

The hydraulic lifting device (5) connects the machine and the work equipment, and also includes a hydraulic cylinder (2) for rotating the lift arm (1) for lifting and lowering the work equipment for raising and lowering the work equipment with respect to the machine. ), and as shown in Figure 4, it includes a solenoid valve (4) for lifting and lowering the work equipment and a slow return valve (4).
In addition to the stop valve (17), a hydraulic pump (18),
It includes a choke valve (19), a relief valve (3) and a safety valve (20).

The microcomputer (16) in the control device (10) is composed of a single chip, and uses a built-in program to time-process the detection signal of the lift arm (1) for lifting and lowering the work machine.
(t+Δt) −, f (t) functions as an operating speed detection means (21) for detecting the operating speed of the working machine, and (, f(t+Δt)−f (t)) /
While generating the rate of change in the vertical speed of f (t),
The detection data from the detector (6) is monitored and set by the setting device (7).
) and has a function as a signal comparison calculation control means (22) for outputting a control signal to the electromagnetic valve drive circuit (13).

In carrying out the present invention, the above-mentioned microcomputer (16) is programmed according to the flowchart shown in FIG. Detection means (11
) for controlling the solenoid valve drive circuit (13) to stop the energization to the solenoid valve (4) for lifting and lowering the work equipment when detecting the stop of data change.
).

Referring to FIG. 5, A is the voltage of the setting device (7) [work machine to machine position setting device (7a)), and is set to v1 to vI by operating the volume on the control panel. B is the detector (6) [lift arm position sensor (6a
) ) is the output voltage of the rotary potentiometer that detects the amount of rotation of the lift arm (1), and under normal and accurate installation, the voltage range is V1%, which is the same as the voltage range of the setting device (7).
It is variable up to VN.

Microcomputer (16) of control device (controller) (10)
) is the voltage “A” indicated by the work equipment to machine position setting device (7a).
If the absolute value of the difference between "' and the voltage 11 B lj indicated by the lift arm position sensor (6a) is greater than a certain range (1/2 of the dead zone P), the signal comparison calculation control means (22
), the direction of deviation in positioning is detected, and the solenoid valve (4) for lifting and lowering the work machine is driven via the solenoid valve drive circuit (13), thereby correcting the position of the work machine. If the setting device (6) (lift arm position sensor (6a)) is misaligned when performing the above operation, the problem shown in FIG. 6 will occur. Setting device (
When 7) is the voltage set to vl, the controller (10) continues to output the solenoid valve actuation signal because the setting device (6) only outputs up to V^, but the hydraulic cylinder (2) is at the end of its stroke, so the relief valve is not activated. (3) is a continuous operation. On the other hand, when the setting device (7) is at V++, positioning is completed when the detector (6) is close to VN (within the dead zone), but the setting of the detector (6) itself is shifted, so the setting device ( The positioning of the working machine ends up being completed at a position deviated from the position in 7).

The dead zone itself should be narrower to improve accuracy,
In that case, the control program was designed so that the above-mentioned continuous operation of the relief valve would not occur even if there was a slight setting error.

The present invention prevents the above-mentioned problems, and the detector (6
) [The detected value of the lift arm position sensor (6a)) is determined by the setting device (7)
) If the set value of ) is not reached, it should naturally change when energizing the solenoid valve (4) for lifting and lowering the work equipment.
The state in which the detected value stops changing before reaching the set value (the detector signal does not change for a finite minute time) is regarded as the end of the stroke, and the energization to the solenoid valve (4) for lifting and lowering the work equipment is stopped. .

That is, the detector (6) [lift arm position sensor (
6a) The data change stop detection means (11) detects a state in which the detected value of ) does not change for a finite minute time, and the work equipment lifting solenoid valve (4) is activated via the drive circuit output stop means (12). This automatically stops energizing.

Effects of the Invention The present invention automatically stops energizing the solenoid valve for lifting and lowering work equipment when the setting device or detector is incorrectly adjusted, and prevents high pressure from occurring due to a shift in stroke end detection time due to malfunction of the detection means. It supplies hydraulic oil to prevent the actuator from being activated, and also prevents the relief valve from operating continuously at the end of the stroke, which has the effect of preventing continuous relief valve operation noise, oil temperature rise, etc.

[Brief explanation of drawings]

・FIG. 1 is a block diagram for responding to complaints regarding a relief valve continuous operation prevention device in an automatic control system for agricultural working machines embodying the present invention, and FIG. 2 is a flowchart as well. FIG. 3 is a block diagram of an automatic control device for agricultural working machines. Fourth
The figure is a hydraulic circuit diagram of a hydraulic lift installation. FIG. 5 is a schematic diagram showing the correspondence between the voltage set by the setting device and the voltage detected by the detector. FIG. 6 is a schematic diagram similar to FIG. 5 showing that continuous operation of the relief valve occurs in the conventional device. 1... Lift arm for lifting and lowering work equipment 2...
・Hydraulic cylinder 3...Relief valve 4...Solenoid valve for lifting work equipment 5...Hydraulic lifting device 6...Detector 7... ... Setting device 10 ... Control device (controller) 11 ...
... Data change stop detection means 12 ... Drive circuit output stop means 13 ... Solenoid valve drive circuit Applicant (516) Seirei Kogyo Co., Ltd. Agent
Patent attorney Fumi Okumura, -1 Figure 5 [A

Claims (1)

[Claims] A hydraulic cylinder (2) that drives the lift arm (1) for lifting and lowering the work machine, a relief valve (3), and a solenoid valve for lifting and lowering the work machine (
4) and a hydraulic lifting device (5) including a detector (6) and a setting device (7) to detect the operation of the solenoid valve (4) for lifting and lowering the work equipment.
) on the basis of the input signal from the signal comparison calculation control means (
22) and a control device (10) for arbitrarily positioning the work machine using a solenoid valve drive circuit (13), etc., wherein the control device (10)
is a data change stop detecting means (11) for detecting the presence or absence of a change in the detector output in an effective minute time, and when the data change stop detecting means (11) detects a stop of data change, Continuous operation of a relief valve in an automatic control device for an agricultural working machine, characterized in that it includes drive circuit output stopping means (12) for controlling a solenoid valve drive circuit (13) to stop energization to a solenoid valve (4). Prevention device.