JP2510037B2 - Lift control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention includes an electromagnetic proportional control valve that sets the operating speed of a hydraulic actuator that drives a ground working device up and down based on a supplied current value. The present invention relates to an elevating control device including deceleration control means for decreasing the supply current to the electromagnetic proportional control valve and decreasing the operating speed when the work device descends from a position near the upper limit to a predetermined set position when the work device descends.

[Conventional technology]

In the above-described lifting control device, conventionally, as shown in, for example, Japanese Patent Laid-Open No. 2-20207, when the working device descends, it descends at a high speed until a predetermined level is reached, and below the predetermined level, the descending speed is reduced. There has been a configuration in which the speed is gradually lowered and the speed switching control is performed by program control in a control device.

[Problems to be Solved by the Invention] In the conventional configuration described above, the working device rushes into the ground at a high speed at the time of headland turning in the field, and the engine is overloaded and stopped or dashing is performed. It suppresses the occurrence of impacts such as.

However, even when the engine is stopped and the work is interrupted in a state where the work device is greatly raised, the slow speed control as described above is executed, so that it takes an extra time until the work device is lowered. There was a flaw.

The present invention aims to solve the above-mentioned problems.

[Means for solving the problem]

The characteristic configuration of the present invention is, in the lifting control device described at the beginning, a detection unit that detects that the engine in the traveling machine body connected to the ground work device is in a stopped state,
And a means for controlling the deceleration operation of the deceleration control means based on the detection operation of the detection means.

[Work]

While the ground work is being performed while the machine body is traveling, the detection means is in the non-detection state, so the restraint means does not operate, and therefore the working device descends at a slow speed. When the engine is stopped due to work interruption or the like, the deceleration control is restrained, so that the work device descends at high speed over the entire stroke.

〔The invention's effect〕

Therefore, according to the present invention, it is possible to effectively prevent a problem such as the occurrence of an overload on the engine during traveling work, but it is possible to minimize wasteful waiting time during non-working, and overall The work efficiency can be improved.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 5, the engine (4) is arranged at the front of the vehicle body (3) having the front and rear wheels (1) and (2), and
A transmission case (5) is arranged at the rear part of the vehicle body (3), a pair of left and right lift arms (6) is provided above the transmission case (5), and a lift cylinder (7) for vertically moving the lift arm (6). ) (An example of a hydraulic actuator) is provided, and at a position above the lift cylinder (7),
A driver's seat (9) is provided between the left and right rear fenders (8) to form an agricultural tractor.

A rotary tiller (11) is provided at the rear end of this agricultural tractor via a two-point link mechanism (10) (an example of a ground work device).
The two-point link mechanism (10) and the lift arm (6) are supported by a pair of left and right lift rods (12) in a suspended state, so that the rotary cultivator (11) includes the shift cylinder. It moves up and down by the drive of (7), and
Since the double-acting rolling cylinder (13) is provided on one of the pair of lift rods (12), the rotary tiller (11) is driven by the rolling cylinder (13) so that the longitudinal axis ( X) is configured to perform a rolling operation around.

A hydraulic system for performing the ascending / descending operation and the rolling operation is represented as shown in FIG. 4. This system includes a hydraulic pump (14) driven by the engine (4) and a flow priority valve (for controlling flow rate) ( 15), the control flow from this flow priority valve (15) is transferred to the rolling cylinder (1
An electromagnetic proportional control valve (V) for supplying the surplus flow from the solenoid valve (16) and the flow priority valve (15) to the lift cylinder (7) or discharging hydraulic oil from the lift cylinder (7). The control valve (V) includes a first valve (17) for raising control and a second valve (18) for controlling pilot pressure for opening and closing the first valve (17).
And a third valve (19) for lowering control, a fourth valve (20) for controlling pilot pressure for opening and closing the third valve (19), and a relief valve (21). When controlling 11) to the ascending side, the solenoid (18
By supplying current to a) and adjusting this current value, the pilot pressure changes corresponding to this current value, and as a result, the valve opening proportional to this current value is obtained, and the rotary tillage is also performed. When the device (11) is controlled to the descending side, the valve opening proportional to this current value is adjusted by adjusting the current value of the current supplied to the solenoid (20a) of the fourth valve (20) as described above. Is configured so that

The vehicle body is provided with a rotation speed detection sensor (S) [an example of detection means] for detecting the rotation speed of the engine (4).

Further, in this agricultural tractor, automatic rotary depth control for raising and lowering the rotary tiller (11) to a predetermined level based on the ground (G) and position control for raising and lowering the rotary tiller (11) to a predetermined level based on the vehicle body (3). And three types of automatic control including rolling control for setting a tilt posture around the longitudinal axis (X), and prioritizing these three types of automatic control, the rotary tiller (11) is installed in a predetermined pair. It is equipped with a control device that performs forced lift control to raise the vehicle body level.

Of this control device, automatic plowing depth control, position control,
The system for performing the forced raising control is configured as shown in Fig. 1. In this configuration, as shown in Fig. 5, the working depth setting dial (23) of the control box (22) provided on the rear fender (8) is set. A first potentiometer (24) for detecting the set position and a second potentiometer (25) for detecting the ground level of the rotary tiller (11) from the swing amount of the swing type rear cover (11a) of the rotary tiller (11). ) And configure the automatic plowing depth control setting system and feedback system,
Further, the third potentiometer (27) for detecting the set position of the position lever (26) arranged on the side of the driver's seat (9) and the rotary tiller (11) are paired from the swing amount of the lift arm (6). A position control setting system and a feedback system are constituted by a fourth potentiometer (28) for detecting the vehicle body level, and a control box (22).
An ascending switch (29) for performing forced ascending control is provided.

It should be noted that in the forced raising control, the fact that the rotary tiller (11) has reached a predetermined level is obtained from the feedback signal from the fourth potentiometer (28).

The signals from these four potentiometers are A / D
Through the converter (30), it is input to the control device (31) equipped with a microprocessor (not shown), and the signal from the raising switch (29) is directly input to the control device (31), and this control is performed. The device (31) outputs an intermittent pulse signal to drive the power transistors (32) and (32), thereby supplying an intermittent pulse current to the solenoids (18a) and (20a). ), (20a), a resistor (R) for converting the current value of the current supplied to the voltage value is interposed in the path (33) from the solenoids (18a), (20a), and in this way The converted voltage value is configured to be fed back to the control device (31) via the feedback path (34) and the A / D converter (30).

Also, this control device adjusts the current value of the current supplied to the solenoids (18a), (20a) by adjusting the duty cycle of the intermittent signal to adjust the opening degree of the control valve (V). The operation speed of the lift cylinder (7) can be changed and adjusted.

Next, an elevating control operation by the control device (31) when the tiller (11) is greatly raised in the headland, turned, and then lowered again will be described.

As shown in FIG. 3, prior to the raising of the tiller (11), the second potentiometers (25) and 4 in the previous step are used.
From the actual measured values of the potentiometer (28) and the characteristics of the link mechanism (10), the aircraft body level (L ₂ ) [target detection value] at which the tilling claw (11b) of the tiller (11) starts to contact the ground is calculated (step S ₁ , S ₂ ). Then, if the compulsory raising operation by the raising switch (29) or the raising operation by operating the position lever (26) is performed, the tilling device (11) is driven to rise (steps S ₃ and S ₄ ), and after turning, the lowering operation is performed. Is performed (step S ₄ ), the engine (4) is not in the stopped state according to the result of the rotation speed sensor (S) (step S ₂₀ ,
S ₂₁ ), the set tilling depth level by the first potentiometer (24) is read (step S ₆ ), and the tiller (11) is thereafter controlled to descend so as to match this level.

That is, as shown in FIG. 2, the tiller (11) descends until the detected value of the fourth potentiometer (28) reaches a set value (L ₁ ) higher than the target detected value (L ₂ ). During this period, the drive current with the maximum duty ratio is supplied to the solenoid proportional control valve (V) and the drive current is lowered at high speed (steps S ₇ , S
₈ ). Then, from the set value (L ₁ ) to the target detection value (L
Up to ₂ ), the lift cylinder (7) and the solenoid proportional control valve (V) correspond to the deviation (Δθ) between the current detection value of the fourth potentiometer (28) and the target detection value (L ₂ ).
The supply current (I) is determined according to the characteristics obtained from the map data based on the characteristics, and the tiller (11) is controlled to descend while gradually lowering the descending speed. (S ₉ , S ₁₀ , S ₁₁ ).
Also, from the target detection value (L ₂ ) until the rear cover (11a) starts to come into contact with the ground, that is, until the second potentiometer (25) reaches a predetermined detection level (P), the minimum current ( I ₁ ) [First set current] is supplied and gradually lowered (steps S ₁₂ and S ₁₃ ). The second set current (I ₂ ) smaller than the first set current (I ₁ ) from the time of touching the rear cover (11a) to the set plowing depth area (within the dead zone width)
Is supplied to further gradually lower (steps S ₁₄ , S ₁₅ ,
S ₁₆ ). After that, the second potentiometer (2
Automatic tilling depth control so that the detected value is maintained at the set tilling depth region of 5) is executed (step S _17).

Then, if it is determined that the engine in step S ₂₁ (4) is in a stopped state, and supplies the driving current of the maximum duty ratio to the control valve (V) to a set tilling depth level, at high speed over the entire stroke Lower (Steps S ₂₂ , S ₂₃ , S
₂₄ ).

Step S ₉ to S ₁₆ by configured deceleration control means (A), constitute a deceleration check means (B) in step S ₂₀ to S _24.

As the engine stop state detecting means, a detecting mechanism such as a hydraulic pump pressure sensor equality may be used instead of the rotation speed sensor.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of a lifting control device according to the present invention.
The figure is a control block diagram, FIG. 2 is a control timing chart, FIG. 3 is a control flowchart, FIG. 4 is a hydraulic circuit diagram, and FIG. 5 is an overall side view of an agricultural tractor. (4) …… Engine, (7) …… Hydraulic actuator,
(11) …… Ground work device, (A) …… Deceleration control means,
(B) ... Checking means, (S) ... Detecting means, (V) ...
Control valve.

Claims (1)

(57) [Claims] 1. A ground work device (11), which comprises an electromagnetic proportional control valve (V) for setting the operating speed of a hydraulic actuator (7) for raising and lowering the ground work device (11) based on the supplied current value. ) In the descending operation of (1), when descending from the vicinity of the upper limit to a predetermined set position, a lifting control device equipped with deceleration control means (A) for reducing the supply current to the electromagnetic proportional control valve (V) and lowering the operating speed. Based on the detection operation of the detection means (S) for detecting that the engine (4) in the traveling machine body connected with the ground work device (11) is in a stopped state, and the detection operation of the detection means (S), A lifting control device comprising means (B) for restraining the deceleration operation of the deceleration control means (A).