JPS5825402B2 - ``Jidōkōshinseigiyosouchi'' - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic plowing depth control device installed in a tractor. This prevents the machine from being raised too high and maintains the appropriate plowing depth.

Attach a working machine such as a rotary to the rear of the tractor body,
When plowing a field, the tractor body sinks in soft ground, and as a result, the plowing depth of the work machine becomes deeper.
Engine speed decreases.

Conventionally, the driver manually operated the control lever of the control valve to change the plowing depth while assessing the situation in order to recover the engine.

However, this operation is very complicated and has the disadvantage of significantly reducing work efficiency.Recently, it has been considered that changes in the load on the engine are detected and the output is used to proportionally control a solenoid valve to raise the work equipment. It's here.

In this case, the lift time of the work equipment is very short compared to the engine recovery time, so if you use an on-off type solenoid valve to perform proportional control, the lift amount of the work equipment will be very large. ,
There is a drawback that the plowing depth may be raised too high and the plowing depth constantly fluctuates unstablely.

The present invention has been provided in order to eliminate such drawbacks, and its features include a device that compares a detected engine rotational speed value with a speed setting value to determine the amount of load fluctuation; an intermittent signal generator that generates an intermittent signal according to the amount of load fluctuation; and a device that uses the intermittent signal to intermittently raise the work equipment while waiting for the engine rotation speed to recover so that the engine rotation speed becomes a set speed. It has the following features.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
The figure shows an example of a tractor equipped with a rotary work machine, in which 1 is the tractor body, front wheels 2, rear wheels 3, engine 4,
It comprises a bonnet 5, an instrument panel 6, a steering handle 77, a driver's seat 8, a hydraulic system 9 for lifting and lowering the working machine, and the like.

The hydraulic system 9 has a pair of left and right lift arms 10.

Reference numeral 11 denotes a rotary working machine, which is equipped with a gauge wheel 12 at the rear, and which connects the tractor body 1 through a three-point link mechanism consisting of a pair of lower links 13 and a top link 14.
The lift arm 10 can be moved up and down via a lift rod 15.

FIG. 2 shows the control device installed on the above tractor.
6 is a rotation speed detector that detects the rotation speed of the engine 4;
A speed setting device 17 is configured to be interlocked with a speed adjustment mechanism of the engine 4, for example, an accelerator lever 18.

Reference numeral 19 denotes a first subtractor, which subtracts the rotational speed detection value B from the speed setting value A set in the speed setting device 17 to detect the load fluctuation of the engine 4.

Reference numeral 20 denotes a load fluctuation discriminator that determines the amount of load fluctuation based on the subtracted value from the first subtractor 19.

21 is an intermittent signal generator, and a third
Generates an intermittent signal as shown in the figure.

That is, the pulse width T1 and pulse interval T2 of the intermittent signal generated by the intermittent signal generator 21 are determined by the load fluctuation discriminator 20.
It is set according to the amount of load fluctuation.

Reference numeral 22 denotes a plowing depth setting device, which is interlocked with a bundle lever 23 provided near the instrument panel 6.

A position detector 24 detects the position of the lift arm 10 in conjunction with the lift arm 10, and the output is maximum when the lift arm 10 is at its highest position.

25 is a second subtractor, which subtracts the tilling depth setting value C of the tilling depth setter 22 and the position detection value C of the position detector 24.

26 is a comparator that discriminates between the subtracted value from the second subtractor 25 and the dead zone set value α, and 27 is a stain magnetic valve 2 based on the comparison output.
This is a switching circuit that switches 8 to ascend, neutral, and descend, respectively.

In the above configuration, when the band lever 23 is operated to a predetermined position, a predetermined plowing depth is set in the plowing depth setting device 22, and the second subtractor 25 calculates the plowing depth setting value C and the position detection value of the position detector 24. Subtract.

If the subtraction value is negative, the set height is lower than the current position of the lift arm 10, so the comparator 26 discriminates between the subtraction value and the dead zone setting α, and if the subtraction value is large, The solenoid valve 28 is operated in the downward direction via the switching circuit 27, and the hydraulic fluid in the hydraulic system 9 is returned to the tank due to the load of the rotary working machine 11, and the rotary working machine 11 is lowered.

When the subtracted value of the second subtractor 25 falls within the dead zone setting value α,
When the solenoid valve 28 is closed via the switching circuit 27, the rotary work machine 11 stops at a predetermined plowing depth set by the plowing depth setting device 22, and the tilling operation is started.

On the other hand, when the rotational speed of the engine 4 is adjusted by the accelerator lever 18, a predetermined speed is set by the speed setting device 17 in conjunction with this.

If the engine 4 is rotating at high speed according to the setting value at that time, the rotational speed detection value B detected by the rotational speed detector 16 and the speed setting value A are the same, and the subtracted value of the first subtractor 19 is Since it is zero, the rotary working machine 11 is kept in a high-speed tilling state at a predetermined tilling depth.

Next, when field conditions change locally, such as on soft ground, both the tractor body 1 and the rotary working machine 11 sink, the load on the engine 4 increases, and the engine rotational speed decreases.

As a result, the rotational speed detection value B of the rotational speed detector 16 becomes small, the first subtractor 19 subtracts the rotational speed detection value B from the speed setting value A to detect load fluctuation, and the subtracted value is used to detect the load fluctuation. The fluctuation discriminator 20 determines the amount of load fluctuation, and sets the pulse width T0 corresponding to this amount of load fluctuation to the intermittent signal generator 21.

If the amount of load fluctuation is large, the pulse width T1 of the intermittent signal shown in FIG. 3 is set to dog, whereas if the amount of load fluctuation is relatively small, the pulse width T is set to be small.

Therefore, the intermittent signal generator 21 begins to generate an intermittent signal with a pulse width T1 corresponding to the amount of load fluctuation, and in synchronization with this intermittent signal, the solenoid valve 28 operates in the upward direction of the work equipment, and the rotary work equipment 11 rise to

That is, when the first pulse signal is input after a load change, the solenoid valve 28 opens by T1 during that time, and the rotary work machine 1
1 rises by a certain amount, the rotary work machine 11 stops rising for a time T2 and waits for the engine 4 to recover, and similarly thereafter, the rotary working machine 11 rises intermittently while waiting for the engine 4 to recover.

By raising for time T1 and waiting for time T2, the recovery of the engine 4 will approximately match the raising characteristics of the rotary work machine 11, and the plowing depth will be very stable without raising too much unlike proportional control. Become.

Furthermore, as the rotational speed of the engine 4 recovers, the subtracted value of the first subtractor 19 becomes smaller sequentially, so the pulse width T1 of the intermittent signal generated by the intermittent signal generator 21 also becomes smaller sequentially, so that the engine 4 As the rotation speed approaches the set rotation speed, the amount of rise of the rotary working machine 11 also decreases, allowing for fine adjustment.

Note that in the example shown, the pulse width T1 is changed, but T
It goes without saying that similar effects can be obtained even if the structure is configured such that 2 is varied.

As described in detail in the embodiments above, in the present invention, the amount of load fluctuation is determined by comparing the detected engine rotational speed value and the speed setting value, and an intermittent signal is generated in accordance with the amount of load fluctuation.
In order for the engine rotation speed to reach the set speed, the construction is such that the work equipment is raised intermittently while waiting for the engine rotation speed to recover using the intermittent signal. can be matched.

The handle generates an intermittent signal according to the amount of load fluctuation, repeatedly raises and stops, waits for the engine speed to recover, and raises the work equipment so that the engine speed reaches the set speed. Even though the recovery of the engine rotational speed is delayed, it is possible to prevent the work equipment from being raised too high.

Therefore, this stabilizes the engine load, and at the same time prevents variations in plowing depth due to rapid lifting of the work implement, making it possible to plow at a stable plowing depth.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, with FIG. 1 being a side view of the whole, FIG. 2 being a block diagram of its control device, and FIG. 3 being a waveform diagram showing an intermittent signal. 1... Tractor body, 9... Hydraulic system, 11...
Rotary work machine, 16...Rotation speed detector, 17...
- Speed setter, 19... First subtractor, 20... Load fluctuation discriminator, 21... Intermittent signal generator, 28... Solenoid valve.

Claims (1)

[Claims] 1. A device that determines the amount of load fluctuation by comparing the engine speed detection value and the speed setting value, an intermittent signal generator that generates an intermittent signal according to the amount of load fluctuation, and an engine speed transfer rate that determines the set speed. An automatic plowing depth control device comprising: a device for intermittently raising the work implement while waiting for the engine speed to recover based on the intermittent signal.